new mpost package drv 0.93 (20sep09)

git-svn-id: svn://tug.org/texlive/trunk@15388 c570f23f-e606-0410-a88d-b1316a301751

17 files changed, 11079 insertions, 0 deletions

diff --git a/Master/texmf-dist/doc/metapost/drv/README b/Master/texmf-dist/doc/metapost/drv/README
new file mode 100644
index 00000000000..e5d287c876f
--- /dev/null
+++ b/Master/texmf-dist/doc/metapost/drv/README
@@ -0,0 +1,21 @@
+drv.mp - derivation trees with MetaPost
+version 0.93
+
+Licence
+lppl
+
+Description
+drv.mp is a set of MetaPost macros for typesetting derivation trees (such as
+used in sequent calculus, type inference, programming language semantics...) 
+NO MetaPost knowledge is needed to use these macros.
+
+Contents
+drv.mp		the main file
+drv-guide.pdf	a user guide attempt
+doc/		the sources for drv-guide.pdf
+sample/		an example of use in conjunction with the beamer class
+template/	a basic set of files for your own tries
+README		this file
+
+Any feedback is welcome.
+laurent.mehats@gmail.com
diff --git a/Master/texmf-dist/doc/metapost/drv/doc/drv-guide.mp b/Master/texmf-dist/doc/metapost/drv/doc/drv-guide.mp
new file mode 100644
index 00000000000..ab6b41675e2
--- /dev/null
+++ b/Master/texmf-dist/doc/metapost/drv/doc/drv-guide.mp
@@ -0,0 +1,1727 @@
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+%
+% Structure of a MetaPost file using drv.mp
+%   1. Preamble
+%        input drv;
+%        verbatimtex %&latex
+%        <LaTeX preamble>
+%        \begin{document}
+%        etex;
+%  2. Figures
+%       <optional drv tunings>
+%       beginfig(<index>)
+%       <judgment & inference declarations>
+%       draw drv_tree;
+%       <optional extra MetaPost code>
+%       endfig;
+%  3. Postamble
+%       end
+%
+
+
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+%
+% 1. Preamble
+%
+
+input drv;
+
+verbatimtex %&latex
+
+% Any piece of code related to font selection in the preamble of
+% `drv-guide.tex' (document class, font package, font selection commands ...)
+% should be reported here.
+
+\documentclass[twoside,11pt]{article}
+\usepackage[T1]{fontenc}
+\usepackage{amsmath}
+\usepackage{amssymb}
+\usepackage{stmaryrd}
+
+% Choose your favourite fonts combination (if available).
+% See "http://ctan.tug.org/tex-archive/info/Free_Math_Font_Survey".
+%
+%\usepackage{cmbright}			% CM text & CM Bright math
+%\usepackage{ccfonts,eulervm}		% Concrete text & Euler math
+%\usepackage{ccfonts}			% Concrete text & math
+%\usepackage[math]{iwona}		% Iwona text & math
+%\usepackage[math]{kurier}		% Kurier text & math
+%\usepackage[math]{anttor}		% Antykwa Torunska text & math
+%\usepackage{kmath,kerkis}		% Kerkis text & math
+%\usepackage{fouriernc}			% New Century Schoolbook & Fourier math
+%\usepackage{pxfonts}			% Palatino & pxfonts math
+%\usepackage{mathpazo}			% Palatino & Pazo math
+%\usepackage{mathpple}			% Palatino & Euler math
+\usepackage[varg]{txfonts}		% Times & txfonts math
+%\usepackage{mathtime}			% Times & Belleek math
+%\usepackage{mathptmx}			% Times & Symbol math
+%\usepackage{mbtimes}			% Omega Serif text & Omega math
+%\usepackage{arev}			% Arev Sans text with Arev math
+%\usepackage[charter]{mathdesign}	% Bitstream Charter & Math Design math
+%\usepackage{comicsans}			% Comic Sans text & math
+%\usepackage[garamond]{mathdesign}	% Garamond & Math Design math
+%\usepackage{fourier}			% Utopia & Fourier math
+%\usepackage[utopia]{mathdesign}	% Utopia & Math Design math
+
+\begin{document}
+etex;
+
+
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+%
+% 2. Figures
+%
+
+%
+% title page
+%
+
+beginfig(100)
+jgm 0 "\Gamma, \Delta, \Theta, \Pi, \Upsilon\vdash F";
+  jgm 1 "\Pi\vdash (A\to D)\to E";
+  jgm 2 "\Gamma, \Delta, \Theta, (A\to D)\to E, \Upsilon\vdash F";
+    jgm 3 "\Gamma, \Delta, \Theta\vdash A\to D";
+      jgm 4 "A, \Gamma, \Delta, \Theta\vdash D";
+        jgm 5 "A, \Gamma, \Delta\vdash B\wedge C";
+          jgm 6 "A, \Gamma\vdash B";
+          jgm 7 "\Delta\vdash C";
+        jgm 8 "B\wedge C, \Theta\vdash D";
+    jgm 9 "E, \Upsilon\vdash F";
+nfr 0 (1, 2) ("\text{cut}", 1);
+  nfr 1 () ("\pi", 4);
+  nfr 2 (3, 9) ("\to_L", 1);
+    nfr 3 (4) ("\to_R", 1);
+      nfr 4 (5, 8) ("\text{cut}", 1);
+        nfr 5 (6, 7) ("\wedge_R", 1);
+          nfr 6 () ("\gamma", 2);
+          nfr 7 () ("\delta", 1);
+        nfr 8 () ("\theta", 3);
+    nfr 9 () ("\upsilon", 2);
+draw drv_tree;
+endfig;
+
+%
+% first example
+%
+
+beginfig(110)
+jgm 0 "A\vdash B";
+jgm 1 "B\vdash C";
+jgm 2 "A\vdash C";
+nfr 0 () ("f", 1);
+nfr 1 () ("g", 1);
+nfr 2 (0, 1) ("\circ", 1);
+draw drv_tree;
+endfig;
+
+%
+% sub-judgments
+%
+
+beginfig(111)
+jgm 0 "A", "\vdash", "B";
+nfr 0 () ("f", 1);
+draw drv_tree;
+endfig;
+
+
+%
+% inference line styles
+%
+
+beginfig(120)
+jgm 0 "\text{none}";
+jgm 1 "\text{simple}";
+jgm 2 "\text{double}";
+jgm 3 "\text{dotted}";
+jgm 4 "\text{dashed}";
+jgm 5 "\text{waved}";
+jgm 6 "\text{\TeX-dotted}";
+jgm 7 "\text{default}";
+nfr 0 ( ) ("\leftarrow 0", 0);
+nfr 1 (0) ("\leftarrow 1", 1);
+nfr 2 (1) ("\leftarrow 2", 2);
+nfr 3 (2) ("\leftarrow 3", 3);
+nfr 4 (3) ("\leftarrow 4", 4);
+nfr 5 (4) ("\leftarrow 5", 5);
+nfr 6 (5) ("\leftarrow 6", 6);
+nfr 7 (6) ("\leftarrow\_", _);
+draw drv_tree;
+endfig;
+
+%
+% declarations order
+%
+
+beginfig(130)
+% preorder declarations
+jgm 0 "0";
+  jgm 1 "00";
+    jgm 2 "000";
+    jgm 3 "001";
+    jgm 4 "002";
+  jgm 5 "01";
+    jgm 6 "010";
+    jgm 7 "011";
+    jgm 8 "012";
+  jgm 9 "02";
+    jgm 10 "020";
+    jgm 11 "021";
+    jgm 12 "022";
+nfr 0 (1, 5, 9) ("a", _);
+  nfr 1 (2, 3, 4) ("b", _);
+    nfr 2 () ("c", _);
+    nfr 3 () ("d", _);
+    nfr 4 () ("e", _);
+  nfr 5 (6, 7, 8) ("f", _);
+    nfr 6 () ("g", _);
+    nfr 7 () ("h", _);
+    nfr 8 () ("i", _);
+  nfr 9 (10, 11, 12) ("j", _);
+    nfr 10 () ("k", _);
+    nfr 11 () ("l", _);
+    nfr 12 () ("m", _);
+draw drv_tree;
+endfig;
+
+beginfig(131)
+% postorder declarations
+    jgm 0 "000";
+    jgm 1 "001";
+    jgm 2 "002";
+  jgm 3 "00";
+    jgm 4 "010";
+    jgm 5 "011";
+    jgm 6 "012";
+  jgm 7 "01";
+    jgm 8 "020";
+    jgm 9 "021";
+    jgm 10 "022";
+  jgm 11 "02";
+jgm 12 "0";
+    nfr 0 () ("a", _);
+    nfr 1 () ("b", _);
+    nfr 2 () ("c", _);
+  nfr 3 (0, 1, 2) ("d", _);
+    nfr 4 () ("e", _);
+    nfr 5 () ("f", _);
+    nfr 6 () ("g", _);
+  nfr 7 (4, 5, 6) ("h", _);
+    nfr 8 () ("i", _);
+    nfr 9 () ("j", _);
+    nfr 10 () ("k", _);
+  nfr 11 (8, 9, 10) ("l", _);
+nfr 12 (3, 7, 11) ("m", _);
+draw drv_tree;
+endfig;
+
+%
+% dcl
+%
+
+beginfig(140)
+dcl 0 () ("f", 1) "A\vdash B";
+dcl 1 () ("g", 1) "B\vdash C";
+dcl 2 (0, 1) ("\circ", 1) "A\vdash C";
+draw drv_tree;
+endfig;
+
+beginfig(141)
+dcl 0 () ("f", 1) "A", "\vdash", "B";
+draw drv_tree;
+endfig;
+
+beginfig(150)
+dcl 0 (1, 5, 9) ("a", _)     "0";
+  dcl 1 (2, 3, 4) ("b", _)     "00";
+    dcl 2 () ("c", _)            "000";
+    dcl 3 () ("d", _)            "001";
+    dcl 4 () ("e", _)            "002";
+  dcl 5 (6, 7, 8) ("f", _)     "01";
+    dcl 6 () ("g", _)            "010";
+    dcl 7 () ("h", _)            "011";
+    dcl 8 () ("i", _)            "012";
+  dcl 9 (10, 11, 12) ("j", _)  "02";
+    dcl 10 () ("k", _)            "020";
+    dcl 11 () ("l", _)            "021";
+    dcl 12 () ("m", _)            "022";
+draw drv_tree;
+endfig;
+
+%
+% bxd
+%
+
+beginfig(160)
+dcl 0 (1, 4) ("", _)     "a";
+  dcl 1 (2) ("", _)      "a";
+    dcl 2 (3) ("", _)    "a";
+      dcl 3 () ("", _)   "aaaaaaa";
+  dcl 4 () ("", _)       "aaaaa";
+draw drv_tree;
+endfig;
+
+beginfig(161)
+dcl 0 (bxd 1, 4) ("", _) "a";
+  dcl 1 (2) ("", _)      "a";
+    dcl 2 (3) ("", _)    "a";
+      dcl 3 () ("", _)   "aaaaaaa";
+  dcl 4 () ("", _)       "aaaaa";
+draw drv_tree;
+endfig;
+
+vardef auxbox[]=
+  ((smin_x[@], ypart iln[ccl[@]].c+iln[ccl[@]].hg)--
+   (smin_x[@], smax_y[@])--
+   (smax_x[@], smax_y[@])--
+   (smax_x[@], ypart iln[ccl[@]].c+iln[ccl[@]].hg)--
+   cycle) shifted (0, min_clr_scl*min_clr[drv_sty]/2)
+enddef;
+
+beginfig(162)
+dcl 0 (bxd 1, 4) ("", _) "a";
+  dcl 1 (2) ("", _)	 "a";
+    dcl 2 (3) ("", _)	 "a";
+      dcl 3 () ("", _)	 "aaaaaaa";
+  dcl 4 () ("", _)	 "aaaaa";
+draw drv_tree;
+draw auxbox[1] withcolor (1, 0, 0);
+endfig;
+
+%
+% mvd
+%
+
+beginfig(170)
+jgm 1 "aaa";
+jgm 2 "bbb";
+jgm 3 "ccc";
+jgm 4 "d";
+nfr 1 () ("", _);
+nfr 2 () ("", _);
+nfr 3 () ("", _);
+nfr 4 (mvd 1 (2, 3), 2, 3) ("", _);
+draw drv_tree;
+endfig;
+
+beginfig(171)
+jgm 1 "aaa";
+jgm 2 "bbb";
+jgm 3 "ccc";
+jgm 4 "d";
+nfr 1 () ("", _);
+nfr 2 () ("", _);
+nfr 3 () ("", _);
+nfr 4 (1, mvd 2 (2, 4), 3) ("", _);
+draw drv_tree;
+endfig;
+
+beginfig(172)
+jgm 1 "aaa";
+jgm 2 "bbb";
+jgm 3 "ccc";
+jgm 4 "d";
+nfr 1 () ("", _);
+nfr 2 () ("", _);
+nfr 3 () ("", _);
+nfr 4 (1, 2, mvd 3 (2, 6)) ("", _);
+draw drv_tree;
+endfig;
+
+beginfig(180)
+jgm 0 "\textsc{Size matters -- Part 1}";
+jgm 1 "\text{Here is a rather long judgment"& % string concatenation
+      " that I don't want to shorten.}";
+jgm 2 "\text{Will the derivation tree fit on the page?}";
+jgm 3 "\text{It does.}";
+nfr 0 () ("", 0);
+nfr 1 (0) ("", 1);
+nfr 2 () ("", 1);
+nfr 3 (mvd 1 (2, 3), 2) ("", 1);
+draw drv_tree;
+endfig;
+
+%
+% Nfr
+%
+
+beginfig(190)
+jgm 0 "a";
+jgm 1 "b";
+jgm 2 "c";
+jgm 3 "d";
+Nfr 0 () ("0", "", "", _);
+Nfr 1 () ("1", "", "", _);
+Nfr 2 (0, 1) ("2", "E", "", _);
+Nfr 3 (2) ("3", "", "F", _);
+draw drv_tree;
+endfig;
+
+%
+% Dcl
+%
+
+beginfig(200)
+Dcl 0 () ("", "", "", _) "a";
+Dcl 1 (0) ("", "", "B", _) "c";
+Dcl 2 () ("", "", "", _) "d";
+Dcl 3 (1, 2) ("", "E", "", _) "f";
+draw drv_tree;
+endfig;
+
+%
+% Mvd
+%
+
+beginfig(210)
+jgm 1 "aaa";
+jgm 2 "bbb";
+jgm 3 "ccc";
+nfr 1 () ("", _);
+nfr 2 () ("", _);
+nfr 3 (Mvd 1 (2, "d", "", 3), 2) ("", _);
+draw drv_tree;
+endfig;
+
+%
+% drv_font_size
+%
+
+drv_font_size "\tiny";
+
+beginfig(220)
+jgm 1 "a";
+jgm 2 "b";
+jgm 3 "c";
+nfr 1 () ("1", 1);
+nfr 2 () ("2", 1);
+Nfr 3 (1, 2) ("3", "4", "", 1);
+draw drv_tree;
+endfig;
+
+drv_font_size "\small";
+
+beginfig(221)
+jgm 1 "a";
+jgm 2 "b";
+jgm 3 "c";
+nfr 1 () ("1", 1);
+nfr 2 () ("2", 1);
+Nfr 3 (1, 2) ("3", "4", "", 1);
+draw drv_tree;
+endfig;
+
+drv_font_size "\Large";
+
+beginfig(222)
+jgm 1 "a";
+jgm 2 "b";
+jgm 3 "c";
+nfr 1 () ("1", 1);
+nfr 2 () ("2", 1);
+Nfr 3 (1, 2) ("3", "4", "", 1);
+draw drv_tree;
+endfig;
+
+drv_font_size "\normalsize";
+
+%
+% drv_math_style (drv, );
+%
+
+beginfig(230)
+jgm 1 "a";
+jgm 2 "b";
+jgm 3 "c";
+nfr 1 () ("1", 1);
+nfr 2 () ("2", 1);
+Nfr 3 (1, 2) ("3", "4", "", 1);
+draw drv_tree;
+endfig;
+
+drv_math_style (drv, "\textstyle");
+
+beginfig(231)
+jgm 1 "a";
+jgm 2 "b";
+jgm 3 "c";
+nfr 1 () ("1", 1);
+nfr 2 () ("2", 1);
+Nfr 3 (1, 2) ("3", "4", "", 1);
+draw drv_tree;
+endfig;
+
+drv_math_style (drv, "\scriptstyle");
+
+beginfig(232)
+jgm 1 "a";
+jgm 2 "b";
+jgm 3 "c";
+nfr 1 () ("1", 1);
+nfr 2 () ("2", 1);
+Nfr 3 (1, 2) ("3", "4", "", 1);
+draw drv_tree;
+endfig;
+
+drv_math_style (drv, "\displaystyle");
+
+%
+% drv_math_style (jdg, );
+%
+
+drv_math_style (jdg, "\displaystyle");
+
+beginfig(240)
+jgm 1 "\bigwedge_{i\in I} A_i";
+jgm 2 "b";
+jgm 3 "c";
+nfr 1 () ("1", 1);
+nfr 2 () ("2", 1);
+Nfr 3 (1, 2) ("3", "4", "", 1);
+draw drv_tree;
+endfig;
+
+drv_math_style (jdg, "\textstyle");
+
+beginfig(241)
+jgm 1 "\bigwedge_{i\in I} A_i";
+jgm 2 "b";
+jgm 3 "c";
+nfr 1 () ("1", 1);
+nfr 2 () ("2", 1);
+Nfr 3 (1, 2) ("3", "4", "", 1);
+draw drv_tree;
+endfig;
+
+drv_math_style (jdg, "\scriptstyle");
+
+beginfig(242)
+jgm 1 "\bigwedge_{i\in I} A_i";
+jgm 2 "b";
+jgm 3 "c";
+nfr 1 () ("1", 1);
+nfr 2 () ("2", 1);
+Nfr 3 (1, 2) ("3", "4", "", 1);
+draw drv_tree;
+endfig;
+
+drv_math_style (jdg, "\textstyle");
+
+%
+% drv_math_style (ilb, );
+%
+
+drv_math_style (ilb, "\textstyle");
+
+beginfig(250)
+jgm 1 "a";
+jgm 2 "b";
+jgm 3 "c";
+nfr 1 () ("1", 1);
+nfr 2 () ("2", 1);
+nfr 3 (1, 2) ("3", 1);
+draw drv_tree;
+endfig;
+
+drv_math_style (ilb, "\scriptstyle");
+
+beginfig(251)
+jgm 1 "a";
+jgm 2 "b";
+jgm 3 "c";
+nfr 1 () ("1", 1);
+nfr 2 () ("2", 1);
+nfr 3 (1, 2) ("3", 1);
+draw drv_tree;
+endfig;
+
+drv_math_style (ilb, "\scriptscriptstyle");
+
+beginfig(252)
+jgm 1 "a";
+jgm 2 "b";
+jgm 3 "c";
+nfr 1 () ("1", 1);
+nfr 2 () ("2", 1);
+nfr 3 (1, 2) ("3", 1);
+draw drv_tree;
+endfig;
+
+drv_math_style (ilb, "\scriptstyle");
+
+%
+% drv_scale (clr, );
+%
+
+drv_scale (clr, 0);
+
+beginfig(260)
+dcl 1 () ("", 1) "\Bigl(a\Bigr)";
+dcl 2 (1) ("", 1) "a";
+draw drv_tree;
+endfig;
+
+drv_scale (clr, 1);
+
+beginfig(261)
+dcl 1 () ("", 1) "\Bigl(a\Bigr)";
+dcl 2 (1) ("", 1) "a";
+draw drv_tree;
+endfig;
+
+drv_scale (clr, 2.5);
+
+beginfig(262)
+dcl 1 () ("", 1) "\Bigl(a\Bigr)";
+dcl 2 (1) ("", 1) "a";
+draw drv_tree;
+endfig;
+
+drv_scale (clr, 4);
+
+beginfig(263)
+dcl 1 () ("", 1) "\Bigl(a\Bigr)";
+dcl 2 (1) ("", 1) "a";
+draw drv_tree;
+endfig;
+
+drv_scale (clr, 1);
+
+%
+% drv_scale (prm, );
+%
+
+drv_scale (prm, 0);
+
+beginfig(270)
+dcl 1 () ("", 1) "a";
+dcl 2 () ("", 1) "a";
+dcl 3 (1, 2) ("", 1) "a";
+draw drv_tree;
+endfig;
+
+drv_scale (prm, 1);
+
+beginfig(271)
+dcl 1 () ("", 1) "a";
+dcl 2 () ("", 1) "a";
+dcl 3 (1, 2) ("", 1) "a";
+draw drv_tree;
+endfig;
+
+drv_scale (prm, 2.5);
+
+beginfig(272)
+dcl 1 () ("", 1) "a";
+dcl 2 () ("", 1) "a";
+dcl 3 (1, 2) ("", 1) "a";
+draw drv_tree;
+endfig;
+
+drv_scale (prm, 4);
+
+beginfig(273)
+dcl 1 () ("", 1) "a";
+dcl 2 () ("", 1) "a";
+dcl 3 (1, 2) ("", 1) "a";
+draw drv_tree;
+endfig;
+
+drv_scale (prm, 1);
+
+%
+% drv_scale (jgm, );
+%
+
+drv_scale (jgm, 0);
+
+beginfig(280)
+dcl 1 () ("", 1) "a";
+dcl 2 () ("", 1) "a";
+dcl 3 (1, 2) ("", 1) "a";
+draw drv_tree;
+endfig;
+
+drv_scale (jgm, 1);
+
+beginfig(281)
+dcl 1 () ("", 1) "a";
+dcl 2 () ("", 1) "a";
+dcl 3 (1, 2) ("", 1) "a";
+draw drv_tree;
+endfig;
+
+drv_scale (jgm, 2.5);
+
+beginfig(282)
+dcl 1 () ("", 1) "a";
+dcl 2 () ("", 1) "a";
+dcl 3 (1, 2) ("", 1) "a";
+draw drv_tree;
+endfig;
+
+drv_scale (jgm, 4);
+
+beginfig(283)
+dcl 1 () ("", 1) "a";
+dcl 2 () ("", 1) "a";
+dcl 3 (1, 2) ("", 1) "a";
+draw drv_tree;
+endfig;
+
+drv_scale (jgm, 1);
+
+%
+% drv_scale (ilb, );
+%
+
+drv_scale (ilb, 0);
+
+beginfig(290)
+dcl 1 () ("b", 1) "a";
+dcl 2 () ("b", 1) "a";
+dcl 3 (1, 2) ("b", 1) "a";
+draw drv_tree;
+endfig;
+
+drv_scale (ilb, 1);
+
+beginfig(291)
+dcl 1 () ("b", 1) "a";
+dcl 2 () ("b", 1) "a";
+dcl 3 (1, 2) ("b", 1) "a";
+draw drv_tree;
+endfig;
+
+drv_scale (ilb, 2.5);
+
+beginfig(292)
+dcl 1 () ("b", 1) "a";
+dcl 2 () ("b", 1) "a";
+dcl 3 (1, 2) ("b", 1) "a";
+draw drv_tree;
+endfig;
+
+drv_scale (ilb, 4);
+
+beginfig(293)
+dcl 1 () ("b", 1) "a";
+dcl 2 () ("b", 1) "a";
+dcl 3 (1, 2) ("b", 1) "a";
+draw drv_tree;
+endfig;
+
+drv_scale (ilb, 1);
+
+%
+% drv_junction_style
+%
+
+path azerty[];
+
+drv_junction_style 0;
+
+beginfig(300)
+dcl 1 ()	("", 1) "aaaaaaaaaaaa";
+dcl 2 (1)	("", 1) "a";
+dcl 3 (2)	("", 1) "a";
+dcl 4 (3)	("", 1) "a";
+dcl 5 (4)	("", 1) "aaaaaa";
+dcl 6 ()	("", 1) "aaaaaa";
+dcl 7 (6)	("", 1) "a";
+dcl 8 (7)	("", 1) "a";
+dcl 9 (5, 8)	("", 1) "a";
+draw drv_tree;
+endfig;
+
+drv_junction_style 1;
+
+beginfig(301)
+dcl 1 ()	("", 1) "aaaaaaaaaaaa";
+dcl 2 (1)	("", 1) "a";
+dcl 3 (2)	("", 1) "a";
+dcl 4 (3)	("", 1) "a";
+dcl 5 (4)	("", 1) "aaaaaa";
+dcl 6 ()	("", 1) "aaaaaa";
+dcl 7 (6)	("", 1) "a";
+dcl 8 (7)	("", 1) "a";
+dcl 9 (5, 8)	("", 1) "a";
+draw drv_tree;
+draw auxbox[8] withcolor .9(1, 1, 1);
+endfig;
+
+drv_junction_style 2;
+
+beginfig(302)
+dcl 1 ()	("", 1) "aaaaaaaaaaaa";
+dcl 2 (1)	("", 1) "a";
+dcl 3 (2)	("", 1) "a";
+dcl 4 (3)	("", 1) "a";
+dcl 5 (4)	("", 1) "aaaaaa";
+dcl 6 ()	("", 1) "aaaaaa";
+dcl 7 (6)	("", 1) "a";
+dcl 8 (7)	("", 1) "a";
+dcl 9 (5, 8)	("", 1) "a";
+draw drv_tree;
+draw auxbox[5] withcolor .9(1, 1, 1);
+draw auxbox[8] withcolor .9(1, 1, 1);
+endfig;
+
+drv_junction_style 1;
+
+%
+% drv_alignment_style
+%
+
+drv_alignment_style l;
+
+beginfig(310)
+dcl 1 () ("", 1) "a";
+dcl 2 () ("", 1) "a";
+dcl 3 (1, 2) ("", 1) "a";
+dcl 4 () ("", 1) "a";
+dcl 5 () ("", 1) "a";
+dcl 6 (4, 5) ("", 1) "a";
+dcl 7 (3, 6) ("", 1) "a";
+draw drv_tree;
+endfig;
+
+drv_alignment_style c;
+
+beginfig(311)
+dcl 1 () ("", 1) "a";
+dcl 2 () ("", 1) "a";
+dcl 3 (1, 2) ("", 1) "a";
+dcl 4 () ("", 1) "a";
+dcl 5 () ("", 1) "a";
+dcl 6 (4, 5) ("", 1) "a";
+dcl 7 (3, 6) ("", 1) "a";
+draw drv_tree;
+endfig;
+
+drv_alignment_style r;
+
+beginfig(312)
+dcl 1 () ("", 1) "a";
+dcl 2 () ("", 1) "a";
+dcl 3 (1, 2) ("", 1) "a";
+dcl 4 () ("", 1) "a";
+dcl 5 () ("", 1) "a";
+dcl 6 (4, 5) ("", 1) "a";
+dcl 7 (3, 6) ("", 1) "a";
+draw drv_tree;
+endfig;
+
+drv_alignment_style c;
+
+%
+% drv_labels_position
+%
+
+drv_labels_position l;
+
+beginfig(320)
+dcl 1 () ("b", 1) "a";
+dcl 2 () ("b", 1) "a";
+dcl 3 (1, 2) ("b", 1) "a";
+draw drv_tree;
+endfig;
+
+drv_labels_position r;
+
+beginfig(321)
+dcl 1 () ("b", 1) "a";
+dcl 2 () ("b", 1) "a";
+dcl 3 (1, 2) ("b", 1) "a";
+draw drv_tree;
+endfig;
+
+%
+% drv_roots_position
+%
+
+drv_roots_position t;
+
+beginfig(330)
+dcl 1 () ("", 1) "a";
+dcl 2 () ("", 1) "a";
+dcl 3 (1, 2) ("", 1) "a";
+dcl 4 () ("", 1) "a";
+dcl 5 () ("", 1) "a";
+dcl 6 (4, 5) ("", 1) "a";
+dcl 7 (3, 6) ("", 1) "a";
+draw drv_tree;
+drv_axis (iln, 3);
+endfig;
+
+drv_roots_position b;
+
+beginfig(331)
+dcl 1 () ("", 1) "a";
+dcl 2 () ("", 1) "a";
+dcl 3 (1, 2) ("", 1) "a";
+dcl 4 () ("", 1) "a";
+dcl 5 () ("", 1) "a";
+dcl 6 (4, 5) ("", 1) "a";
+dcl 7 (3, 6) ("", 1) "a";
+draw drv_tree;
+endfig;
+
+%
+% drv_axis_reference
+%
+
+beginfig(340)
+dcl 1 () ("", 1) "a";
+dcl 2 () ("", 1) "a";
+dcl 3 (1, 2) ("", 1) "a";
+draw drv_tree;
+endfig;
+
+drv_axis_reference jdg;
+
+beginfig(341)
+dcl 1 () ("", 1) "a";
+dcl 2 () ("", 1) "a";
+dcl 3 (1, 2) ("", 1) "a";
+draw drv_tree;
+endfig;
+
+drv_axis_reference iln;
+
+%
+% drv_left_delimiter
+%
+
+drv_left_delimiter "(";
+
+beginfig(350)
+dcl 1 () ("", 1) "a";
+Dcl 2 (1) ("", "", "B", 1) "c";
+dcl 3 () ("", 1) "d";
+Dcl 4 (2, 3) ("", "E", "", 1) "f";
+draw drv_tree;
+endfig;
+
+drv_left_delimiter "\lfloor";
+
+beginfig(351)
+dcl 1 () ("", 1) "a";
+Dcl 2 (1) ("", "", "B", 1) "c";
+dcl 3 () ("", 1) "d";
+Dcl 4 (2, 3) ("", "E", "", 1) "f";
+draw drv_tree;
+endfig;
+
+drv_left_delimiter ".";
+
+beginfig(352)
+dcl 1 () ("", 1) "a";
+Dcl 2 (1) ("", "", "B", 1) "c";
+dcl 3 () ("", 1) "d";
+Dcl 4 (2, 3) ("", "E", "", 1) "f";
+draw drv_tree;
+endfig;
+
+drv_left_delimiter "\lbrace";
+
+%
+% drv_right_delimiter
+%
+
+drv_right_delimiter "\rangle";
+
+beginfig(360)
+dcl 1 () ("", 1) "a";
+Dcl 2 (1) ("", "", "B", 1) "c";
+dcl 3 () ("", 1) "d";
+Dcl 4 (2, 3) ("", "E", "", 1) "f";
+draw drv_tree;
+endfig;
+
+drv_right_delimiter "\uparrow";
+
+beginfig(361)
+dcl 1 () ("", 1) "a";
+Dcl 2 (1) ("", "", "B", 1) "c";
+dcl 3 () ("", 1) "d";
+Dcl 4 (2, 3) ("", "E", "", 1) "f";
+draw drv_tree;
+endfig;
+
+drv_right_delimiter ".";
+
+beginfig(362)
+dcl 1 () ("", 1) "a";
+Dcl 2 (1) ("", "", "B", 1) "c";
+dcl 3 () ("", 1) "d";
+Dcl 4 (2, 3) ("", "E", "", 1) "f";
+draw drv_tree;
+endfig;
+
+drv_right_delimiter "\rbrace";
+
+%
+% drv_box_mode
+%
+
+drv_box_mode on;
+
+beginfig(370)
+dcl 0 ()	("", 1) "aaaaa";
+dcl 1 ()	("", 1) "aaaaaaa";
+dcl 2 (1)	("", 1) "a";
+dcl 3 (2)	("", 1) "a";
+dcl 4 (0, 3)	("", 1) "a";
+draw drv_tree;
+endfig;
+
+beginfig(371)
+dcl 0 ()	("", 1) "aaaaa";
+dcl 1 ()	("", 1) "aaaaaaa";
+dcl 2 (1)	("", 1) "a";
+dcl 3 (2)	("", 1) "a";
+dcl 4 (0, 3)	("", 1) "a";
+draw drv_tree;
+for idx=0, 1, 2, 3:
+  draw auxbox[idx] withcolor (1, 0, 0);
+endfor
+endfig;
+
+drv_box_mode off;
+
+beginfig(372)
+dcl 0 ()	("", 1) "aaaaa";
+dcl 1 ()	("", 1) "aaaaaaa";
+dcl 2 (1)	("", 1) "a";
+dcl 3 (2)	("", 1) "a";
+dcl 4 (0, 3)	("", 1) "a";
+draw drv_tree;
+endfig;
+
+%
+% drv_fraction_mode
+%
+
+beginfig(380)
+jgm 0 "\overbrace{A, \Gamma\vdash B}";
+jgm 1 "B, \Delta\vdash C";
+jgm 2 "A, \Gamma, \Delta\vdash C";
+jgm 3 "\Gamma, \Delta\vdash A\to C";
+nfr 0 () ("", 0);
+nfr 1 () ("", 1);
+nfr 2 (0, 1) ("\text{cut}", 1);
+nfr 3 (2) ("\to_R", 1);
+draw drv_tree;
+endfig;
+
+drv_fraction_mode off;
+
+beginfig(381)
+jgm 0 "\overbrace{A, \Gamma\vdash B}";
+jgm 1 "B, \Delta\vdash C";
+jgm 2 "A, \Gamma, \Delta\vdash C";
+jgm 3 "\Gamma, \Delta\vdash A\to C";
+nfr 0 () ("", 0);
+nfr 1 () ("", 1);
+nfr 2 (0, 1) ("\text{cut}", 1);
+nfr 3 (2) ("\to_R", 1);
+draw drv_tree;
+endfig;
+
+drv_fraction_mode on;
+
+beginfig(382)
+jgm 0 "\overbrace{A, \Gamma\vdash B}";
+jgm 1 "B, \Delta\vdash C";
+jgm 2 "A, \Gamma, \Delta\vdash C";
+jgm 3 "\Gamma, \Delta\vdash A\to C";
+nfr 0 () ("", 1);
+nfr 1 () ("", 1);
+nfr 2 (0, 1) ("\text{cut}", 1);
+nfr 3 (2) ("\to_R", 1);
+draw drv_tree;
+unfill bbox iln[0];
+draw iln[0] withcolor (1, 0, 0);
+endfig;
+
+%
+% drv_proof_mode
+%
+
+drv_proof_mode on;
+
+beginfig(390)
+jgm 0 "A", "\vdash", "A";
+jgm 1 "B", "\vdash", "B";
+jgm 2 "A", ",", "A", "\multimap", "B", "\vdash", "B";
+jgm 3 "A", "\multimap", "B", "\vdash", "A", "\multimap", "B";
+nfr 0 () ("1", 1);
+nfr 1 () ("1", 1);
+nfr 2 (0, 1) ("\multimap_{L}", 1);
+nfr 3 (2) ("\multimap_{R}", 1);
+draw drv_tree;
+endfig;
+
+drv_proof_mode off;
+
+beginfig(391)
+jgm 0 "A", "\vdash", "A";
+jgm 1 "B", "\vdash", "B";
+jgm 2 "A", ",", "A", "\multimap", "B", "\vdash", "B";
+jgm 3 "A", "\multimap", "B", "\vdash", "A", "\multimap", "B";
+nfr 0 () ("1", 1);
+nfr 1 () ("1", 1);
+nfr 2 (0, 1) ("\multimap_{L}", 1);
+nfr 3 (2) ("\multimap_{R}", 1);
+draw drv_tree;
+endfig;
+
+%
+% a fraction
+%
+
+drv_math_style (drv, "\textstyle");
+drv_scale (jgm, 0);
+
+beginfig(400)
+dcl 0 ( ) ("", 0) "\gamma";
+dcl 1 (0) ("", 1) "\delta";
+draw drv_tree;
+endfig;
+
+drv_math_style (drv, "\displaystyle");
+drv_scale (jgm, 1);
+
+%
+% drv_bbox
+%
+
+beginfig(410)
+dcl 0 (1, 5) ("", _)  "a";
+  dcl 1 (2, 3, 4) ("", _)   "b";
+    dcl 2 () ("", _)          "c";
+    dcl 3 () ("", _)          "d";
+    dcl 4 () ("", _)          "e";
+  dcl 5 () ("", _)          "f";
+fill drv_bbox 1 withcolor (255, 230, 205)/255; % rgb color
+draw drv_tree;
+endfig;
+
+beginfig(411)
+dcl 0 (bxd 1, 5) ("", _)  "a";
+  dcl 1 (2, 3, 4) ("", _)   "b";
+    dcl 2 () ("", _)          "c";
+    dcl 3 () ("", _)          "d";
+    dcl 4 () ("", _)          "e";
+  dcl 5 () ("", _)          "f";
+fill drv_bbox 1 withcolor (255, 230, 205)/255; % rgb color
+draw drv_tree;
+endfig;
+
+%
+% drv_axis
+%
+
+beginfig(420)
+Dcl 0 ( ) ("",   "", "", _) "a";
+Dcl 1 (0) ("", "{}", "", _) "b";
+draw drv_tree;
+drv_axis (iln, 0);
+endfig;
+
+beginfig(421)
+Dcl 0 ( ) ("",   "", "", _) "a";
+Dcl 1 (0) ("", "{}", "", _) "b";
+draw drv_tree;
+drv_axis (jdg, 1);
+endfig;
+
+beginfig(422)
+Dcl 0 ( ) ("",   "", "", _) "a";
+Dcl 1 (0) ("", "{}", "", _) "b";
+draw drv_tree;
+drv_axis (dlm, 1);
+endfig;
+
+%
+% NFR
+%
+
+beginfig(430)
+jgm 0 "a";
+NFR 0 () ("1", "2", "3", "4", _, _, _);
+draw drv_tree;
+endfig;
+
+%
+% DCL
+%
+
+beginfig(440)
+DCL 0 ()     ("1", "", "", "", _, _, _) "a";
+DCL 1 ()     ("", "2", "", "", _, _, _) "b";
+DCL 2 (0, 1) ("", "", "3", "", _, _, _) "c";
+DCL 3 (2)    ("", "", "", "4", _, _, _) "d";
+draw drv_tree;
+endfig;
+
+%
+% MVD
+%
+
+beginfig(450)
+jgm 0 "aaaaaa";
+jgm 1 "aaa";
+jgm 2 "a";
+jgm 3 "aaaaaaaaa";
+jgm 4 "a";
+nfr 0 () ("", _);
+NFR 1 () ("", "", "", "", _, _, _);
+nfr 2 (MVD 0 (2, "A", "", l, 3), 1) ("", _);
+nfr 3 () ("", _);
+nfr 4 (2, MVD 3 (5, "", "A", r, 4)) ("", _);
+draw drv_tree;
+endfig;
+
+beginfig(460)
+jgm 0 "\textsc{Size matters -- Part 2}";
+jgm 1 "\text{Here is an even longer judgment"&
+      " that I don't want to shorten either.}";
+jgm 2 "\text{This time I'm pretty sure that the"&
+      " derivation tree won't fit on the page.}";
+jgm 3 "\text{It does! Amazing.}";
+nfr 0 () ("", 0);
+nfr 1 (0) ("", 1);
+nfr 2 () ("", 1);
+nfr 3 (MVD 1 (2, "", "", l, 3), 2) ("", 1);
+draw drv_tree;
+endfig;
+
+%
+% Components and central points
+%
+
+drv_font_size "\large";
+
+beginfig(470) % components
+DCL 6 () ("", "", "", "", _, _, 0) "0";
+DCL 7 (6) ("(1)", "(2)", "(3)", "(4)", _, _, 1) "A", "B";
+drv_freeze; % usually called by drv_tree
+draw jdg[6];                        % judgment               0
+draw sbj[7][0] withcolor (0, 0, 1); % sub-judgment           A
+draw sbj[7][1] withcolor (0, 1, 0); % sub-judgment           B
+draw l_ilb[7]  withcolor (0, 1, 1); % left inference label  (1)
+draw r_ilb[7]  withcolor (1, 0, 0); % right inference label (2)
+draw l_dlb[7]  withcolor (1, 0, 1); % left delimiter label  (3)
+draw r_dlb[7]  withcolor (1, 1, 0); % right delimiter label (4)
+draw l_dlm[7];                      % left delimiter
+draw iln[7];                        % inference line
+draw r_dlm[7];                      % right delimiter
+endfig;
+
+beginfig(471) % central points
+DCL 6 () ("", "", "", "", _, _, 0) "0";
+DCL 7 (6) ("(1)", "(2)", "(3)", "(4)", _, _, 1) "A", "B";
+pickup pencircle scaled 2.5;
+draw drv_tree withcolor .75(1, 1, 1);
+draw jdg[6].c;                        % judgment               0
+draw sbj[7][0].c withcolor (0, 0, 1); % sub-judgment           A
+draw sbj[7][1].c withcolor (0, 1, 0); % sub-judgment           B
+draw l_ilb[7].c  withcolor (0, 1, 1); % left inference label  (1)
+draw r_ilb[7].c  withcolor (1, 0, 0); % right inference label (2)
+draw l_dlb[7].c  withcolor (1, 0, 1); % left delimiter label  (3)
+draw r_dlb[7].c  withcolor (1, 1, 0); % right delimiter label (4)
+draw l_dlm[7].c;                       % left delimiter
+draw iln[7].c;                         % inference line
+draw r_dlm[7].c;                       % right delimiter
+endfig;
+
+drv_font_size "\normalsize";
+
+%
+% Dimensions
+%
+
+vardef aux_drawdblarrow expr pth=
+save ah;
+path ah;
+ah:=ahlength*(dir (180-ahangle/2))--(0, 0)--
+    ahlength*(dir (180+ahangle/2));
+if direction infinity of pth<>(0, 0):
+  draw pth;
+  draw ah rotated (angle (direction infinity of pth))
+    shifted (point infinity of pth);
+  draw ah rotated (180+angle (direction -infinity of pth))
+    shifted (point -infinity of pth);
+fi
+enddef;
+
+drv_box
+  "jdg_ma[]",
+  "jdg_cp[]",
+  "jdg_hg[]",
+  "jdg_dp[]",
+  "iln_cp[]",
+  "n_hg",
+  "d_dp";
+for idx=0, 1:
+  box_init jdg_ma[idx](mth_tex[1]"\textit{math axis}");
+  box_init jdg_cp[idx](mth_tex[2]"\texttt{jdg["&decimal idx&"].c}");
+  box_init jdg_hg[idx](mth_tex[1]"\texttt{jdg["&decimal idx&"].hg}");
+  box_init jdg_dp[idx](mth_tex[1]"\texttt{jdg["&decimal idx&"].dp}");
+  box_init iln_cp[idx](mth_tex[2]"\texttt{iln["&decimal idx&"].c}");
+endfor
+box_init n_hg(mth_tex[1]"\texttt{num\_hg}");
+box_init d_dp(mth_tex[1]"\texttt{den\_dp}");
+
+drv_font_size "\fontsize{95}{0}";
+
+beginfig(480)
+dcl 0 ()  ("", 0) "\gamma";
+dcl 1 (0) ("", 1) "\delta";
+draw drv_tree withcolor .75*background;
+interim linejoin:=beveled;
+interim ahangle:=60;
+lref[0]:=xpart iln[1].l-20pt;
+lref[1]:=xpart iln[1].l-10pt;
+lref[2]:=xpart iln[1].l-25pt;
+rref[0]:=xpart iln[1].r+20pt;
+rref[1]:=xpart iln[1].r+10pt;
+rref[2]:=xpart iln[1].r+25pt;
+for idx=0, 1:
+  forsuffixes sfx=l, c ,r:
+    draw jdg[idx].sfx withpen pencircle scaled 2.5;
+  endfor
+  lx[idx]:=xpart jdg[idx].l;
+  rx[idx]:=xpart jdg[idx].r;
+  ty[idx]:=ypart jdg[idx].c+jdg[idx].hg;
+  cy[idx]:=ypart jdg[idx].c;
+  by[idx]:=ypart jdg[idx].c+jdg[idx].dp;
+  for pth=
+    (lx[idx], ty[idx])--(rref[0], ty[idx]),
+    (lref[0], cy[idx])--(rref[0], cy[idx]),
+    (lx[idx], by[idx])--(rref[0], by[idx]),
+    (lx[idx], ty[idx])--(lx[idx], by[idx]),
+    (rx[idx], ty[idx])--(rx[idx], by[idx]):
+      draw pth dashed evenly scaled .5;
+  endfor
+  for pth=
+    (rref[1], ty[idx])--(rref[1], cy[idx]),
+    (rref[1], cy[idx])--(rref[1], by[idx]):
+      aux_drawdblarrow pth;
+  endfor
+  jdg_ma[idx].r=(lref[2], cy[idx]);
+  jdg_cp[idx].c=jdg[idx].c shifted (0, -7.5pt);
+  jdg_hg[idx].l=(rref[2], (ty[idx]+cy[idx])/2);
+  jdg_dp[idx].l=(rref[2], (cy[idx]+by[idx])/2);
+  forsuffixes sfx=jdg_ma, jdg_cp, jdg_hg, jdg_dp:
+    box_freeze sfx[idx];
+    draw sfx[idx];
+  endfor
+endfor
+draw iln[1].c withpen pencircle scaled 2.5;
+iln_cp[1].c=iln[1].c shifted (0, -7.5pt);
+box_freeze iln_cp[1];
+draw iln_cp[1];
+iln_y:=ypart iln[1].c;
+draw (lref[0], iln_y)--(rref[0], iln_y) dashed evenly scaled .5;
+aux_drawdblarrow (lref[1], cy[0])--(lref[1], iln_y);
+aux_drawdblarrow (lref[1], iln_y)--(lref[1], cy[1]);
+n_hg.r=(lref[2], (cy[0]+iln_y)/2);
+d_dp.r=(lref[2], (iln_y+cy[1])/2);
+forsuffixes sfx=n_hg, d_dp:
+  box_freeze sfx;
+  draw sfx;
+endfor
+endfig;
+
+drv_font_size "\normalsize";
+
+%
+% drv_styled
+%
+
+beginfig(490)
+jgm 4 "A", "\vdash", "A";
+jgm 5 "B", "\vdash", "B";
+jgm 6 "A", ",", "A", "\multimap", "B", "\vdash", "B";
+jgm 7 "A", "\multimap", "B", "\vdash", "A", "\multimap", "B";
+nfr 4 () ("1", _);
+nfr 5 () ("1", _);
+nfr 6 (4, 5) ("\multimap_{L}", _);
+nfr 7 (6) ("\multimap_{R}", _);
+drv_freeze;
+draw (sbj[7][2].c shifted (0, -num_hg) ..
+      sbj[7][2].c {up} ..
+      sbj[6][4].c ..
+      sbj[5][0].c .. tension 1.05 ..
+      sbj[5][2].c ..
+      sbj[6][6].c ..
+      sbj[7][6].c {down} ..
+      sbj[7][6].c shifted (0, -num_hg))
+drv_styled 2 withcolor (1, 0, 0);
+draw drv_tree;
+endfig;
+
+%
+% ``User specified'' junction style
+%
+
+beginfig(500)
+jgm 0 "{\cdot}";
+jgm 1 "{\cdot}";
+jgm 2 "\text{You may check that the distance"&
+      " between the two dots above is 5 cm.}";
+NFR 0 () ("", "", "", "", _, _, _);
+NFR 1 () ("", "", "", "", _, _, _);
+NFR 2 (0, 1) ("", "", "", "", 3, _, _); % caution: 3
+xpart jdg[1].c=xpart jdg[0].c+5cm;
+draw drv_tree;
+endfig;
+
+%
+% ``User specified'' alignment style
+%
+
+beginfig(510)                                          % "\vdash":
+jgm 0 "B, A, \Gamma", "\vdash", "C";                   % sbj[0][1]
+jgm 1 "A, \Gamma", "\vdash", "B\multimap C";           % sbj[1][1]
+jgm 2 "\Gamma", "\vdash", "A\multimap(B\multimap C)";  % sbj[2][1]
+NFR_opt 0 () () () (_, _, 0);
+NFR_opt 1 (0) ("\multimap_R") () (_, u, 1);            % caution: u
+NFR_opt 2 (1) ("\multimap_R") () (_, u, 1);            % caution: u
+xpart sbj[1][1].c=xpart sbj[0][1].c;
+xpart sbj[2][1].c=xpart sbj[1][1].c;
+draw drv_tree;
+endfig;
+
+beginfig(511)                                          % "\vdash":
+jgm 0 "B, A, \Gamma", "\vdash", "C";                   % sbj[0][1]
+jgm 1 "A, \Gamma", "\vdash", "B\multimap C";           % sbj[1][1]
+jgm 2 "\Gamma", "\vdash", "A\multimap(B\multimap C)";  % sbj[2][1]
+NFR_opt 0 () () () (_, _, 0);
+NFR_opt 1 (0) ("\multimap_R") () (_, u, 1);            % caution: u
+NFR_opt 2 (1) ("\multimap_R") () (_, u, 1);            % caution: u
+xpart sbj[1][1].l=xpart sbj[0][1].r;
+xpart sbj[2][1].l=xpart sbj[1][1].r;
+draw drv_tree;
+endfig;
+
+%
+% debugging
+%
+
+beginfig(520)
+jgm 0 "A\vdash B";
+jgm 1 "B\vdash C";
+jgm 2 "A\vdash C";
+jgm 3 "C\vdash D";
+jgm 4 "A\vdash D";
+nfr 0 () ("f", _);
+nfr 1 () ("g", _);
+nfr 2 (0, 1) ("\circ", _);
+nfr 3 () ("h", _);
+nfr 4 (2, 3) ("\circ", _);
+draw drv_tree;
+endfig;
+
+%
+% example - Restall
+%
+
+string Lor, Ror[], Land[], Rand;
+Lor:="\vee L";
+Ror1:="\vee R_1";
+Ror2:="\vee R_2";
+Land1:="\wedge L_1";
+Land2:="\wedge L_2";
+Rand:="\wedge R";
+
+beginfig(530)
+jgm 0 "p\wedge(q\vee(r_1\wedge r_2))\vdash p\wedge(q\vee(r_1\wedge r_2))";
+  jgm 1 "p\wedge(q\vee(r_1\wedge r_2))\vdash p";
+    jgm 2 "p\vdash p";
+  jgm 3 "p\wedge(q\vee(r_1\wedge r_2))\vdash q\vee(r_1\wedge r_2)";
+    jgm 4 "q\vee(r_1\wedge r_2)\vdash q\vee(r_1\wedge r_2)";
+      jgm 5 "q\vdash q\vee(r_1\wedge r_2)";
+        jgm 6 "q\vdash q";
+      jgm 7 "r_1\wedge r_2\vdash q\vee(r_1\wedge r_2)";
+        jgm 8 "r_1\wedge r_2\vdash r_1\wedge r_2";
+          jgm 9 "r_1\wedge r_2\vdash r_1";
+            jgm 10 "r_1\vdash r_1";
+          jgm 11 "r_1\wedge r_2\vdash r_2";
+            jgm 12 "r_2\vdash r_2";
+nfr 0 (1, 3) (Rand, 1);
+  nfr 1 (2) (Land1, 1);
+    nfr 2 () ("", 0);
+  nfr 3 (bxd 4) (Land2, 1);		% fig. 531 -> nfr 3 (mvd 4 (1, 3))
+    nfr 4 (5, 7) (Lor, 1);		% fig. 531 -> Nfr
+      nfr 5 (6) (Ror1, 1);
+        nfr 6 () ("", 0);
+      nfr 7 (bxd 8) (Ror2, 1);		% fig. 531 -> nfr 7 (mvd 8 (1, 3))
+        nfr 8 (9, 11) (Rand, 1);	% fig. 531 -> Nfr
+          nfr 9 (10) (Land1, 1);
+            nfr 10 () ("", 0);
+          nfr 11 (12) (Land2, 1);
+            nfr 12 () ("", 0);
+fill drv_bbox 4 withcolor (255, 230, 205)/255;
+fill drv_bbox 8 withcolor (236, 211, 185)/255;
+draw drv_tree;
+endfig;
+
+beginfig(531)
+jgm 0 "p\wedge(q\vee(r_1\wedge r_2))\vdash p\wedge(q\vee(r_1\wedge r_2))";
+  jgm 1 "p\wedge(q\vee(r_1\wedge r_2))\vdash p";
+    jgm 2 "p\vdash p";
+  jgm 3 "p\wedge(q\vee(r_1\wedge r_2))\vdash q\vee(r_1\wedge r_2)";
+    jgm 4 "q\vee(r_1\wedge r_2)\vdash q\vee(r_1\wedge r_2)";
+      jgm 5 "q\vdash q\vee(r_1\wedge r_2)";
+        jgm 6 "q\vdash q";
+      jgm 7 "r_1\wedge r_2\vdash q\vee(r_1\wedge r_2)";
+        jgm 8 "r_1\wedge r_2\vdash r_1\wedge r_2";
+          jgm 9 "r_1\wedge r_2\vdash r_1";
+            jgm 10 "r_1\vdash r_1";
+          jgm 11 "r_1\wedge r_2\vdash r_2";
+            jgm 12 "r_2\vdash r_2";
+nfr 0 (1, 3) (Rand, 1);
+  nfr 1 (2) (Land1, 1);
+    nfr 2 () ("", 0);
+  nfr 3 (mvd 4 (1, 3)) (Land2, 1);
+    Nfr 4 (5, 7) (Lor, "\text{Id\,}_{q\vee(r_1\wedge r_2)}", "", 1);
+      nfr 5 (6) (Ror1, 1);
+        nfr 6 () ("", 0);
+      nfr 7 (mvd 8 (1, 3)) (Ror2, 1);
+        Nfr 8 (9, 11) (Rand, "\text{Id\,}_{r_1\wedge r_2}", "", 1);
+          nfr 9 (10) (Land1, 1);
+            nfr 10 () ("", 0);
+          nfr 11 (12) (Land2, 1);
+            nfr 12 () ("", 0);
+fill drv_bbox 4 withcolor (255, 230, 205)/255;
+fill drv_bbox 8 withcolor (236, 211, 185)/255;
+draw drv_tree;
+endfig;
+
+%
+% example - Roegel
+%
+
+drv_junction_style 0;
+drv_scale (jdg, 0.85);
+drv_scale (prm, 0.85);
+
+vardef mix[]=
+  "\textit{mix}("&(decimal @)&")"
+enddef;
+
+beginfig(540)
+jgm 0 "\Gamma_A, \Gamma'\vdash\Delta, \Delta'_A";
+  jgm 1 "\Gamma_A, \Gamma', \Gamma_A, \Gamma', \Gamma_A, \Gamma'\vdash"&
+    "\Delta, \Delta'_A, \Delta, \Delta'_A, \Delta, \Delta'_A";
+    jgm 2 "\Gamma_A, \Gamma', \Gamma_A\vdash"&    % a space character is
+      " C, \Delta, \Delta'_A, \Delta, \Delta'_A"; % needed before 'C'!
+      jgm 3 "\Gamma_A, \Gamma'\vdash B, C, \Delta, \Delta'_A";
+        jgm 4 "\Gamma, B\vee C\vdash \Delta";
+          jgm 5 "\Gamma, B\vdash \Delta";
+            jgm 6 "\Pi_1";
+          jgm 7 "\Gamma, C\vdash \Delta";
+            jgm 8 "\Pi_2";
+        jgm 9 "\Gamma'\vdash B, C, \Delta'";
+          jgm 10 "\Pi_3";
+      jgm 11 "\Gamma_A, \Gamma', B\vdash\Delta, \Delta'_A";
+        jgm 12 "\Gamma, B\vdash \Delta";
+          jgm 13 "\Pi_1";
+        jgm 14 "\Gamma'\vdash B\vee C, \Delta'";
+          jgm 15 "\Gamma'\vdash B, C, \Delta'";
+            jgm 16 "\Pi_3";
+    jgm 17 "\Gamma_A, \Gamma', C\vdash\Delta, \Delta'_A";
+      jgm 18 "\Gamma, C\vdash \Delta";
+        jgm 19 "\Pi_2";
+      jgm 20 "\Gamma'\vdash B\vee C, \Delta'";
+        jgm 21 "\Gamma'\vdash B, C, \Delta'";
+          jgm 22 "\Pi_3";
+nfr 0 (1) ("\text{contr$_g$, contr$_d$}", 1);
+  nfr 1 (2, 17) (mix5, 1);
+    nfr 2 (mvd 3 (5, 6), 11) (mix3 , 1);
+      nfr 3 (4, 9) (mix1, 1);
+        nfr 4 (5, 7) ("\vee_g", 1);
+          nfr 5 (mvd 6 (1, 6)) ("", 0);
+            nfr 6 () ("", 0);
+          nfr 7 (mvd 8 (1, 6)) ("", 0);
+            nfr 8 () ("", 0);
+        nfr 9 (mvd 10 (1, 6)) ("", 0);
+          nfr 10 () ("", 0);
+      nfr 11 (12, 14) ("", 1);
+        nfr 12 (mvd 13 (1, 6)) ("", 0);
+          nfr 13 () ("", 0);
+        nfr 14 (15) ("", 1);
+          nfr 15 (mvd 16 (1, 6)) ("", 0);
+            nfr 16 () ("", 0);
+    nfr 17 (18, 20) (mix4, 1);
+      nfr 18 (mvd 19 (1, 6)) ("", 0);
+        nfr 19 () ("", 0);
+      nfr 20 (21) ("\vee_d", 1);
+        nfr 21 (mvd 22 (1, 6)) ("", 0);
+          nfr 22 () ("", 0);
+draw drv_tree;
+endfig;
+
+drv_junction_style 1;
+drv_scale (jdg, 1);
+drv_scale (prm, 1);
+
+%
+% example - Lutz
+%
+
+drv_math_style (ilb, "\textstyle");
+drv_labels_position (ilb, l);
+drv_scale (clr, 1.5);
+
+string neg, par, otm;
+neg:="^\bot";
+par:="\mathbin{\bindnasrepma}"; % from stmaryrd.sty
+otm:="\otimes";
+
+beginfig(550)
+    %  0    1    2    3    4    5    6    7    8    9
+jgm 0 "a", neg, par, "a";
+jgm 1 "a", neg, par, "(", "a", otm, "(", "a", par, "a", neg, ")", ")";
+jgm 2 "a", neg, par, "(", "a", otm, "a", ")", par, "a", neg;
+jgm 3 "a", neg, par, "(", "a", otm, "a", ")", par, "(",
+      "(", "a", par, "a", neg, ")", otm, "a", neg, ")";
+jgm 4 "a", neg, par, "(", "a", otm, "a", ")", par, "a",
+      par, "(", "a", neg, otm, "a", neg, ")";
+nfr 0 ( ) ("\textsf{id}", 1);
+nfr 1 (0) ("\textsf{id}", 1);
+nfr 2 (1) ("\textsf{s}",  1);
+nfr 3 (2) ("\textsf{id}", 1);
+nfr 4 (3) ("\textsf{s}",  1);
+drv_freeze;
+drawoptions (withpen drv_pen scaled 2 withcolor (255, 94, 94)/255);
+draw
+  sbj[4][12].c shifted (0, -num_hg) .. {up}
+  sbj[4][12].c ..
+  sbj[3][13].c .. tension .9 ..
+  sbj[3][11].c ..
+  sbj[4][9].c {down} ..
+  sbj[4][9].c shifted (0, -num_hg);
+draw
+  sbj[4][15].c shifted (0, -num_hg) .. {up}
+  sbj[4][15].c ..
+  sbj[3][17].c .. tension 1.2 ..
+  sbj[2][9].c ..
+  sbj[1][9].c {up} .. tension 1.5.. {down}
+  sbj[1][7].c ..
+  sbj[2][6].c .. tension 1.2 ..
+  sbj[3][6].c ..
+  sbj[4][6].c {down} ..
+  sbj[4][6].c shifted (0, -num_hg);
+draw
+  sbj[4][0].c shifted (0, -num_hg) .. {up}
+  sbj[4][0].c ..
+  sbj[3][0].c .. tension 1.2 ..
+  sbj[2][0].c ..
+  sbj[1][0].c .. tension 1.2 ..
+  sbj[0][0].c {up} .. tension 1.8.. {down}
+  sbj[0][3].c .. tension 1.2 ..
+  sbj[1][4].c ..
+  sbj[2][4].c .. tension 1.2 ..
+  sbj[3][4].c ..
+  sbj[4][4].c {down} ..
+  sbj[4][4].c shifted (0, -num_hg);
+drawoptions ();
+draw drv_tree; % fig. 551 -> draw jdg[4];
+endfig;
+
+beginfig(551)
+    %  0    1    2    3    4    5    6    7    8    9
+jgm 0 "a", neg, par, "a";
+jgm 1 "a", neg, par, "(", "a", otm, "(", "a", par, "a", neg, ")", ")";
+jgm 2 "a", neg, par, "(", "a", otm, "a", ")", par, "a", neg;
+jgm 3 "a", neg, par, "(", "a", otm, "a", ")", par, "(",
+      "(", "a", par, "a", neg, ")", otm, "a", neg, ")";
+jgm 4 "a", neg, par, "(", "a", otm, "a", ")", par, "a",
+      par, "(", "a", neg, otm, "a", neg, ")";
+nfr 0 ( ) ("\textsf{id}", 1);
+nfr 1 (0) ("\textsf{id}", 1);
+nfr 2 (1) ("\textsf{s}",  1);
+nfr 3 (2) ("\textsf{id}", 1);
+nfr 4 (3) ("\textsf{s}",  1);
+drv_freeze;
+drawoptions (withpen drv_pen scaled 2 withcolor (255, 94, 94)/255);
+draw
+  sbj[4][12].c shifted (0, -num_hg) .. {up}
+  sbj[4][12].c ..
+  sbj[3][13].c .. tension .9 ..
+  sbj[3][11].c ..
+  sbj[4][9].c {down} ..
+  sbj[4][9].c shifted (0, -num_hg);
+draw
+  sbj[4][15].c shifted (0, -num_hg) .. {up}
+  sbj[4][15].c ..
+  sbj[3][17].c .. tension 1.2 ..
+  sbj[2][9].c ..
+  sbj[1][9].c {up} .. tension 1.5.. {down}
+  sbj[1][7].c ..
+  sbj[2][6].c .. tension 1.2 ..
+  sbj[3][6].c ..
+  sbj[4][6].c {down} ..
+  sbj[4][6].c shifted (0, -num_hg);
+draw
+  sbj[4][0].c shifted (0, -num_hg) .. {up}
+  sbj[4][0].c ..
+  sbj[3][0].c .. tension 1.2 ..
+  sbj[2][0].c ..
+  sbj[1][0].c .. tension 1.2 ..
+  sbj[0][0].c {up} .. tension 1.8.. {down}
+  sbj[0][3].c .. tension 1.2 ..
+  sbj[1][4].c ..
+  sbj[2][4].c .. tension 1.2 ..
+  sbj[3][4].c ..
+  sbj[4][4].c {down} ..
+  sbj[4][4].c shifted (0, -num_hg);
+drawoptions ();
+draw jdg[4]; % fig. 550 -> draw drv_tree;
+endfig;
+
+drv_math_style (ilb, "\scriptstyle");
+drv_labels_position (ilb, r);
+drv_scale (clr, 1);
+
+%
+% a continued fraction
+%
+
+drv_math_style (ilb, "\textstyle");
+drv_scale (jdg, 0);
+drv_scale (ilb, 0);
+drv_labels_position (ilb, l);
+drv_roots_position t;
+drv_box_mode on;
+
+drv_font_size "\normalsize";
+
+beginfig(560)
+dcl 0 (1) ("1+", 1) "a";
+dcl 1 (2) ("2+", 1) "b";
+dcl 2 (3) ("3+", 1) "c";
+dcl 3 (4) ("4+", 1) "d";
+dcl 4 ( ) ("", 0) "\cdots";
+draw drv_tree;
+endfig;
+
+drv_math_style (ilb, "\scriptstyle");
+drv_scale (jdg, 1);
+drv_scale (ilb, 1);
+drv_labels_position (ilb, r);
+drv_roots_position b;
+drv_box_mode off;
+
+
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+%
+% 3. Postamble
+%
+
+end
diff --git a/Master/texmf-dist/doc/metapost/drv/doc/drv-guide.tex b/Master/texmf-dist/doc/metapost/drv/doc/drv-guide.tex
new file mode 100644
index 00000000000..48a7644a517
--- /dev/null
+++ b/Master/texmf-dist/doc/metapost/drv/doc/drv-guide.tex
@@ -0,0 +1,1864 @@
+% Any piece of code related to font selection in the following preamble
+% (document class, font package, font selection commands ...) should be
+% reported in `drv-guide.mp'.
+
+\documentclass[twoside,11pt]{article}
+\usepackage[T1]{fontenc}
+\usepackage{amsmath}
+\usepackage{amssymb}
+\usepackage{stmaryrd}
+
+% Choose your favourite fonts combination (if available).
+% See "http://ctan.tug.org/tex-archive/info/Free_Math_Font_Survey".
+%
+%\usepackage{cmbright}			% CM text & CM Bright math
+%\usepackage{ccfonts,eulervm}		% Concrete text & Euler math
+%\usepackage{ccfonts}			% Concrete text & math
+%\usepackage[math]{iwona}		% Iwona text & math
+%\usepackage[math]{kurier}		% Kurier text & math
+%\usepackage[math]{anttor}		% Antykwa Torunska text & math
+%\usepackage{kmath,kerkis}		% Kerkis text & math
+%\usepackage{fouriernc}			% New Century Schoolbook & Fourier math
+%\usepackage{pxfonts}			% Palatino & pxfonts math
+%\usepackage{mathpazo}			% Palatino & Pazo math
+%\usepackage{mathpple}			% Palatino & Euler math
+\usepackage[varg]{txfonts}		% Times & txfonts math
+%\usepackage{mathtime}			% Times & Belleek math
+%\usepackage{mathptmx}			% Times & Symbol math
+%\usepackage{mbtimes}			% Omega Serif text & Omega math
+%\usepackage{arev}			% Arev Sans text with Arev math
+%\usepackage[charter]{mathdesign}	% Bitstream Charter & Math Design math
+%\usepackage{comicsans}			% Comic Sans text & math
+%\usepackage[garamond]{mathdesign}	% Garamond & Math Design math
+%\usepackage{fourier}			% Utopia & Fourier math
+%\usepackage[utopia]{mathdesign}	% Utopia & Math Design math
+
+\usepackage{mflogo}
+\usepackage{array}
+\usepackage{multicol}
+\raggedcolumns
+\usepackage{fancyvrb}
+\fvset{fontsize=\small}
+\usepackage{color}
+\definecolor{myblue}{rgb}{0,0,.5}
+
+\usepackage{hyperref}
+\hypersetup{colorlinks=true}
+\hypersetup{citecolor=myblue}
+\hypersetup{linkcolor=myblue}
+\hypersetup{urlcolor=myblue}
+\hypersetup{pdftitle={drv.mp - derivation trees with MetaPost}}
+\hypersetup{pdfauthor={Laurent M\'ehats}}
+
+% Picture inclusion macro: \drv
+%
+% \drv includes a picture file in such a way that the baseline of the included
+% picture coincides with the baseline of the inclusion point. The code for \drv
+% was suggested by Josselin Noirel on the fr.comp.text.tex usenet group.
+
+\usepackage{graphicx}
+\makeatletter
+\def\Gin@def@bp#1\relax#2#3{\gdef#2{#3}}
+\newsavebox{\graphicsbox}
+\newcommand*{\drv}[1]{%
+\sbox{\graphicsbox}{\includegraphics{#1}}%
+\raisebox{\Gin@lly bp}%
+{\usebox{\graphicsbox}}}
+\makeatother
+
+\newcommand{\param}[1]{\textrm{\textit{$\langle$#1\/$\rangle$}}}
+\newcommand{\default}[1][]{\emph{$*$ default#1 $*$}}
+\newcommand{\tbs}{\textbackslash}
+\newcommand{\resplap}{\llap{\textrm{\emph{resp. }}}}
+
+\title{\texttt{drv.mp}\\
+derivation trees with \MP%
+\thanks{You don't need to know \MP\ to use this package.}\\
+{\small almost a user's guide%
+\thanks{Feel free to improve! (E.g. by correcting the poor English.)
+Last update: \today.}}}
+\author{Laurent \textsc{M\'ehats}\\
+{\small\href{mailto:laurent.mehats@gmail.com}
+{\texttt{laurent.mehats@gmail.com}}}}
+\date{documented version: 0.93}
+
+\pagestyle{myheadings}
+\renewcommand{\sectionmark}[1]{%
+\markboth{\upshape\sc#1}{}}
+\renewcommand{\subsectionmark}[1]{%
+\markright{\upshape\thesubsection\quad#1}}
+
+\begin{document}
+\maketitle
+%
+%
+\begin{gather*}
+\drv{drv-guide.100}
+\end{gather*}
+%
+%
+\tableofcontents
+%
+%
+\section{Usage\label{sec-usage}}
+%
+%
+\subsection{Structure of a \MP\ file using \texttt{drv.mp}%
+\label{sec-structure}}
+%
+%
+\begin{description}
+\item[Preamble]\
+  \begin{Verbatim}[commandchars=\\\{\}]
+  input drv;
+  verbatimtex %&latex
+  \param{\LaTeX\ preamble}
+  \texttt{\tbs{}begin\{document\}}
+  etex;
+  \end{Verbatim}
+\item[Figures]\
+  \begin{Verbatim}[commandchars=\\\{\}]
+  \param{optional \texttt{drv} tunings}
+  beginfig(\param{index})
+    \param{judgment \& inference declarations}
+    draw drv_tree;
+    \param{optional extra \MP\ code}
+  endfig;
+  \end{Verbatim}
+\item[Postamble]\
+  \begin{Verbatim}
+  end
+  \end{Verbatim}
+\end{description}
+For each ``\texttt{beginfig(\param{index})}, \texttt{endfig;}'' pair in a file
+\texttt{\param{jobname}.mp}, \MP\ generates an Encapsulated PostScript file
+\texttt{\param{jobname}.\param{index}}.
+%
+%
+\subsection{Running \MP\label{sec-running}}
+%
+%
+You have to run \emph{at least twice}
+\begin{center}
+\texttt{mpost \param{jobname}.mp}
+\end{center}
+(once more if you use sub-tree delimiters, see~\S~\ref{sec-sub-tree}). On the
+first run \MP\ collects the \LaTeX\ code generated by \texttt{drv.mp}
+declaration macros and writes it to the file
+\texttt{\param{jobname}-delayed.mp}. On the second run \MP\ preprocesses the
+\LaTeX\ code in \texttt{\param{jobname}-delayed.mp} and then typesets the
+derivation trees.
+
+If you get an error on the first run then it comes from the
+\texttt{drv.mp}/\MP\ code. If you get an error on the second run then it comes
+from the \LaTeX\ code. In both cases, correct the error (see
+Appendix~\ref{sec-debugging}), delete \texttt{\param{jobname}-delayed.mp} and
+run ``\texttt{mpost \param{jobname}.mp}'' twice again (a \texttt{makefile} can
+do that for you).
+%
+%
+\subsection{\LaTeX\ inclusion commands\label{sec-inclusion}}
+%
+%
+Encapsulated PostScript files \texttt{\param{jobname}.\param{index}} generated
+by \MP\ can be included in \LaTeX\ documents using the
+\texttt{\tbs{}includegraphics\{\param{jobname}.\param{index}\}}
+command from the \texttt{graphicx.sty} (or \texttt{graphics.sty}) package%
+\footnote{You may get standalone picture files (e.g. transparent \textsc{png}
+for inclusion in a webpage) from each \texttt{\param{jobname}.\param{index}}
+file as described in Appendix~\ref{sec-standalone}.}.
+
+However \texttt{drv.mp} provides ways to set the baseline of
+derivation tree pictures  (see~\S~\ref{sec-axis-reference}
+ and~\S~\ref{sec-axis}). Then I suggest using the following
+\texttt{\tbs{}drv\{\param{jobname}.\param{index}\}} command which is
+such that the baseline of the included picture coincides with the baseline of
+the inclusion point.
+\begin{Verbatim}
+\usepackage{graphicx}
+\makeatletter
+\def\Gin@def@bp#1\relax#2#3{\gdef#2{#3}}
+\newsavebox{\graphicsbox}
+\newcommand*{\drv}[1]{%
+\sbox{\graphicsbox}{\includegraphics{#1}}%
+\raisebox{\Gin@lly bp}%
+{\usebox{\graphicsbox}}}
+\makeatother
+\end{Verbatim}
+The code for \texttt{\tbs{}drv} was suggested by Josselin
+\textsc{Noirel} on the \texttt{fr.comp.text.tex} Usenet group.
+%
+%
+\section{Judgment \& inference declarations\label{sec-declarations}}
+%
+%
+\subsection{\texttt{jgm} \& \texttt{nfr}\label{sec-jgm-nfr}}
+%
+%
+\texttt{jgm \param{nat} \param{str list}}\\
+\begin{tabular}{ll}
+\param{nat}&		judgment index\\
+\param{str list}&	sub-judgments \emph{math-mode} \LaTeX\ code
+\end{tabular}\\[1ex]
+\texttt{nfr \param{nat} (\param{nat list}) (\param{str}, \param{id})}\\
+\begin{tabular}{ll}
+\param{nat}&		inference index\\
+\param{nat list}&	list of premise indices\\
+\param{str}&		inference label \emph{math-mode} \LaTeX\ code\\
+\param{id}&		inference line style identifier ({\tt0}, {\tt1},
+			{\tt2}, {\tt3},	{\tt4}, {\tt5}, {\tt6} or {\tt\_})
+\end{tabular}\\[1ex]
+``\texttt{jgm} \param{nat}'' declares a judgment which index is
+\param{nat} while ``\texttt{nfr} \param{nat}'' declares an inference which
+conclusion is the index \param{nat} judgment (a judgment may be declared before
+or after the corresponding inference, no matter).
+
+A premise index \param{nat} refers to the sub-tree ending with the index
+\param{nat} judgment. A list of premise indices may be arbitrary long.
+%
+%
+\begin{multicols}{2}
+\paragraph{First example}
+%
+%
+%\begin{multicols}{2}
+\begin{Verbatim}
+beginfig(110)
+jgm 0 "A\vdash B";
+jgm 1 "B\vdash C";
+jgm 2 "A\vdash C";
+nfr 0 () ("f", 1);
+nfr 1 () ("g", 1);
+nfr 2 (0, 1) ("\circ", 1);
+draw drv_tree;
+endfig;
+\end{Verbatim}
+\columnbreak
+
+\begin{gather*}
+\drv{drv-guide.110}
+\end{gather*}
+\end{multicols}
+%
+%
+\paragraph{Sub-judgments}
+%
+%
+\begin{multicols}{2}
+\begin{Verbatim}
+beginfig(111)
+jgm 0 "A", "\vdash", "B";
+nfr 0 () ("f", 1);
+draw drv_tree;
+endfig;
+\end{Verbatim}
+\columnbreak
+
+\begin{gather*}
+\drv{drv-guide.111}
+\end{gather*}
+\end{multicols}
+\noindent
+The outputs induced by
+\begin{center}
+\texttt{jgm 0 "A\tbs{}vdash B";}\qquad and\qquad
+\texttt{jgm 0 "A", "\tbs{}vdash", "B";}
+\end{center}
+are the same. Using the latter declaration, you can manipulate sub-judgments
+independently from each-other (see \S~\ref{sec-components}).
+%
+%
+\paragraph{Inference line styles}
+%
+%
+\begin{multicols}{2}
+\begin{Verbatim}
+beginfig(120)
+jgm 0 "\text{none}";
+jgm 1 "\text{simple}";
+jgm 2 "\text{double}";
+jgm 3 "\text{dotted}";
+jgm 4 "\text{dashed}";
+jgm 5 "\text{waved}";
+jgm 6 "\text{\TeX-dotted}";
+jgm 7 "\text{default}";
+nfr 0 ( ) ("\leftarrow 0", 0);
+nfr 1 (0) ("\leftarrow 1", 1);
+nfr 2 (1) ("\leftarrow 2", 2);
+nfr 3 (2) ("\leftarrow 3", 3);
+nfr 4 (3) ("\leftarrow 4", 4);
+nfr 5 (4) ("\leftarrow 5", 5);
+nfr 6 (5) ("\leftarrow 6", 6);
+nfr 7 (6) ("\leftarrow\_", _);
+draw drv_tree;
+endfig;
+\end{Verbatim}
+\columnbreak
+
+\begin{gather*}
+\drv{drv-guide.120}
+\end{gather*}
+\end{multicols}
+\noindent
+The default inference line style is set by the \texttt{drv\_path\_style} macro
+(see \S~\ref{sec-path-style}).
+%
+%
+\paragraph{Declarations order}
+%
+%
+Declarations may occur in any order.
+\begin{multicols}{2}
+\begin{Verbatim}
+beginfig(130)
+% preorder declarations
+jgm 0 "0";
+  jgm 1 "00";
+    jgm 2 "000";
+    jgm 3 "001";
+    jgm 4 "002";
+  jgm 5 "01";
+    jgm 6 "010";
+    jgm 7 "011";
+    jgm 8 "012";
+  jgm 9 "02";
+    jgm 10 "020";
+    jgm 11 "021";
+    jgm 12 "022";
+nfr 0 (1, 5, 9) ("a", _);
+  nfr 1 (2, 3, 4) ("b", _);
+    nfr 2 () ("c", _);
+    nfr 3 () ("d", _);
+    nfr 4 () ("e", _);
+  nfr 5 (6, 7, 8) ("f", _);
+    nfr 6 () ("g", _);
+    nfr 7 () ("h", _);
+    nfr 8 () ("i", _);
+  nfr 9 (10, 11, 12) ("j", _);
+    nfr 10 () ("k", _);
+    nfr 11 () ("l", _);
+    nfr 12 () ("m", _);
+draw drv_tree;
+endfig;
+\end{Verbatim}
+\columnbreak
+\begin{Verbatim}
+beginfig(131)
+% postorder declarations
+    jgm 0 "000";
+    jgm 1 "001";
+    jgm 2 "002";
+  jgm 3 "00";
+    jgm 4 "010";
+    jgm 5 "011";
+    jgm 6 "012";
+  jgm 7 "01";
+    jgm 8 "020";
+    jgm 9 "021";
+    jgm 10 "022";
+  jgm 11 "02";
+jgm 12 "0";
+    nfr 0 () ("a", _);
+    nfr 1 () ("b", _);
+    nfr 2 () ("c", _);
+  nfr 3 (0, 1, 2) ("d", _);
+    nfr 4 () ("e", _);
+    nfr 5 () ("f", _);
+    nfr 6 () ("g", _);
+  nfr 7 (4, 5, 6) ("h", _);
+    nfr 8 () ("i", _);
+    nfr 9 () ("j", _);
+    nfr 10 () ("k", _);
+  nfr 11 (8, 9, 10) ("l", _);
+nfr 12 (3, 7, 11) ("m", _);
+draw drv_tree;
+endfig;
+\end{Verbatim}
+\end{multicols}
+\begin{gather*}
+\drv{drv-guide.130}\tag{130}\\[1ex]
+\drv{drv-guide.131}\tag{131}
+\end{gather*}
+%
+%
+\paragraph{Code for the title page derivation tree}
+%
+%
+\begin{Verbatim}
+beginfig(100)
+jgm 0 "\Gamma, \Delta, \Theta, \Pi, \Upsilon\vdash F";
+  jgm 1 "\Pi\vdash (A\to D)\to E";
+  jgm 2 "\Gamma, \Delta, \Theta, (A\to D)\to E, \Upsilon\vdash F";
+    jgm 3 "\Gamma, \Delta, \Theta\vdash A\to D";
+      jgm 4 "A, \Gamma, \Delta, \Theta\vdash D";
+        jgm 5 "A, \Gamma, \Delta\vdash B\wedge C";
+          jgm 6 "A, \Gamma\vdash B";
+          jgm 7 "\Delta\vdash C";
+        jgm 8 "B\wedge C, \Theta\vdash D";
+    jgm 9 "E, \Upsilon\vdash F";
+nfr 0 (1, 2) ("\text{cut}", 1);
+  nfr 1 () ("\pi", 4);
+  nfr 2 (3, 9) ("\to_L", 1);
+    nfr 3 (4) ("\to_R", 1);
+      nfr 4 (5, 8) ("\text{cut}", 1);
+        nfr 5 (6, 7) ("\wedge_R", 1);
+          nfr 6 () ("\gamma", 2);
+          nfr 7 () ("\delta", 1);
+        nfr 8 () ("\theta", 3);
+    nfr 9 () ("\upsilon", 2);
+draw drv_tree;
+endfig;
+\end{Verbatim}
+%
+%
+\subsection{\texttt{dcl}\label{sec-dcl}}
+%
+%
+\texttt{dcl} enables the simultaneous declarations of a judgment and of the
+corresponding inference:
+%\begin{center}
+``\texttt{dcl \param{nat} (\param{nat list})
+(\param{str}, \param{id}) \param{str list}}''
+%\end{center}
+is a shorthand for
+``\texttt{jgm \param{nat} \param{str list}; nfr \param{nat} (\param{nat list})
+(\param{str}, \param{id})}''.
+\begin{multicols}{2}
+\begin{Verbatim}
+beginfig(140)
+dcl 0 () ("f", 1) "A\vdash B";
+dcl 1 () ("g", 1) "B\vdash C";
+dcl 2 (0, 1) ("\circ", 1) "A\vdash C";
+draw drv_tree;
+endfig;
+
+beginfig(141)
+dcl 0 () ("f", 1) "A", "\vdash", "B";
+draw drv_tree;
+endfig;
+\end{Verbatim}
+\columnbreak
+
+\begin{gather*}
+\drv{drv-guide.140}
+\end{gather*}
+\vfill
+\begin{gather*}
+\drv{drv-guide.141}
+\end{gather*}
+\end{multicols}
+\begin{Verbatim}
+beginfig(150)
+dcl 0 (1, 5, 9) ("a", _)     "0";
+  dcl 1 (2, 3, 4) ("b", _)     "00";
+    dcl 2 () ("c", _)            "000";
+    dcl 3 () ("d", _)            "001";
+    dcl 4 () ("e", _)            "002";
+  dcl 5 (6, 7, 8) ("f", _)     "01";
+    dcl 6 () ("g", _)            "010";
+    dcl 7 () ("h", _)            "011";
+    dcl 8 () ("i", _)            "012";
+  dcl 9 (10, 11, 12) ("j", _)  "02";
+    dcl 10 () ("k", _)            "020";
+    dcl 11 () ("l", _)            "021";
+    dcl 12 () ("m", _)            "022";
+draw drv_tree;
+endfig;
+\end{Verbatim}
+\begin{gather*}
+\drv{drv-guide.150}
+\end{gather*}
+%
+%
+\subsection{\texttt{bxd} \& \texttt{mvd}\label{sec-bxd-mvd}}
+%
+%
+\paragraph{\texttt{bxd}}
+%
+%
+A premise index \param{nat} can be replaced with ``\texttt{bxd \param{nat}}''
+so that the whole sub-tree ending with the index \param{nat} judgment behaves
+as if it was enclosed within a box.
+\begin{Verbatim}[commandchars=\\\{\}]
+beginfig(160)
+dcl 0 (1, 4) ("", _)     "a";
+\resplap{}dcl 0 (bxd 1, 4) ("", _) "a";
+  dcl 1 (2) ("", _)      "a";
+    dcl 2 (3) ("", _)    "a";
+      dcl 3 () ("", _)   "aaaaaaa";
+  dcl 4 () ("", _)       "aaaaa";
+draw drv_tree;
+endfig;
+\end{Verbatim}
+\begin{gather*}
+\drv{drv-guide.160}\quad\text{resp.}\quad
+\drv{drv-guide.161}\quad\text{typeset as}\quad
+\drv{drv-guide.162}
+\end{gather*}
+%
+%
+\paragraph{\texttt{mvd}}
+%
+%
+A premise index \param{nat 1} in an inference declaration can be replaced with
+``\texttt{mvd \param{nat 1} (\param{nat 2}, \param{id})}'' so as to declare
+\param{nat 2} ``phantom'' inference steps starting from the index \param{nat 1}
+judgment. The ``phantom'' inference steps are intended to be drawn as
+a path using the path-style \param{id}.\\[1ex]
+\texttt{mvd \param{nat 1} (\param{nat 2}, \param{id})}\\
+\begin{tabular}{ll}
+\param{nat 1}&	index of the origin judgment\\
+\param{nat 2}&	number of phantom steps\\
+\param{id}&	phantom steps path-style identifier ({\tt0}, {\tt1}, {\tt2},
+		{\tt3},	{\tt4}, {\tt5}, {\tt6} or {\tt\_})
+\end{tabular}
+\begin{multicols}{2}
+\begin{Verbatim}[commandchars=\\\{\}]
+beginfig(170)
+jgm 1 "aaa";
+jgm 2 "bbb";
+jgm 3 "ccc";
+jgm 4 "d";
+nfr 1 () ("", _);
+nfr 2 () ("", _);
+nfr 3 () ("", _);
+nfr 4 (mvd 1 (2, 3), 2, 3) ("", _);
+\resplap{}nfr 4 (1, mvd 2 (2, 4), 3) ("", _);
+\resplap{}nfr 4 (1, 2, mvd 3 (2, 6)) ("", _);
+draw drv_tree;
+endfig;
+\end{Verbatim}
+\columnbreak
+\begin{gather*}
+\drv{drv-guide.170}\\[1ex]
+\drv{drv-guide.171}\\[1ex]
+\drv{drv-guide.172}
+\end{gather*}
+\end{multicols}
+\begin{Verbatim}[commandchars=\\\{\}]
+beginfig(180)
+jgm 0 "\tbs{}textsc\{Size matters -- Part 1\}";
+jgm 1 "\tbs{}text\{Here is a rather long judgment"&\textrm{\emph{
+ % string concatenation}}
+      " that I don't want to shorten.\}";
+jgm 2 "\tbs{}text\{Will the derivation tree fit on the page?\}";
+jgm 3 "\tbs{}text\{It does.\}";
+nfr 0 () ("", 0);
+nfr 1 (0) ("", 1);
+nfr 2 () ("", 1);
+nfr 3 (mvd 1 (2, 3), 2) ("", 1);
+draw drv_tree;
+endfig;
+\end{Verbatim}
+\begin{gather*}
+\drv{drv-guide.180}
+\end{gather*}
+%The default phantom steps path-style ``''is set by the
+%\texttt{drv\_path\_style} macro (see~\S~\ref{sec-path-style}).
+%
+%
+\subsection{Sub-tree delimiters \& labels\label{sec-sub-tree}}
+%
+%
+\paragraph{\texttt{Nfr}}
+%
+%
+The \texttt{Nfr} declaration macro is an alternative for \texttt{nfr} that
+enables the typesetting of delimiters.\\[1ex]
+\texttt{Nfr \param{nat} (\param{nat list})
+(\param{str 1}, \param{str 2}, \param{str 3}, \param{id})}\\
+\begin{tabular}{ll}
+\param{nat}&		inference index\\
+\param{nat list}&	list of premise indices\\
+\param{str 1}&		inference label \emph{math-mode} \LaTeX\ code\\
+\param{str 2}&		left delimiter label \emph{math-mode} \LaTeX\ code\\
+\param{str 3}&		right delimiter label \emph{math-mode} \LaTeX\ code\\
+\param{id}&		inference line style identifier ({\tt0}, {\tt1},
+			{\tt2}, {\tt3},	{\tt4}, {\tt5}, {\tt6} or {\tt\_})
+\end{tabular}\\[1ex]
+If both \param{str 2} and \param{str 3} are the empty string
+\texttt{""} then \texttt{Nfr} behaves exactly like \texttt{nfr}. However, if
+\param{str 2} is a non-empty string then a delimiter is placed to the left of
+the sub-tree ending with the index \param{nat} judgment and \param{str 2} is
+attached to it as a label. The same way, if \param{str 3} is a non-empty
+string then a delimiter is placed to the right of the sub-tree ending with the
+index \param{nat} judgment and \param{str 3} is attached to it as a label. Both
+\param{str 2} and \param{str 3} may be non-empty strings. You may use
+\texttt{"\{\}"} as a string argument to get a delimiter without a label.
+\begin{multicols}{2}
+\begin{Verbatim}
+beginfig(190)
+jgm 0 "a";
+jgm 1 "b";
+jgm 2 "c";
+jgm 3 "d";
+Nfr 0 () ("0", "", "", _);
+Nfr 1 () ("1", "", "", _);
+Nfr 2 (0, 1) ("2", "E", "", _);
+Nfr 3 (2) ("3", "", "F", _);
+draw drv_tree;
+endfig;
+\end{Verbatim}
+\columnbreak
+
+\begin{gather*}
+\drv{drv-guide.190}
+\end{gather*}
+\end{multicols}
+%
+%
+\paragraph{\texttt{Dcl}}
+%
+%
+The \texttt{Dcl} declaration macro is a shorthand for \texttt{jgm} and
+\texttt{Nfr} in the same way as \texttt{dcl} is a shorthand for \texttt{jgm}
+and \texttt{nfr}.
+\begin{multicols}{2}
+\begin{Verbatim}
+beginfig(200)
+Dcl 0 () ("", "", "", _) "a";
+Dcl 1 (0) ("", "", "B", _) "c";
+Dcl 2 () ("", "", "", _) "d";
+Dcl 3 (1, 2) ("", "E", "", _) "f";
+draw drv_tree;
+endfig;
+\end{Verbatim}
+\columnbreak
+
+\begin{gather*}
+\drv{drv-guide.200}
+\end{gather*}
+\end{multicols}
+%
+%
+\paragraph{\texttt{Mvd}}
+%
+%
+The \texttt{Mvd} macro is an alternative for \texttt{mvd} that enables the
+attachment of labels to phantom steps paths.\\[1ex]
+\texttt{Mvd \param{nat 1}
+(\param{nat 2}, \param{str 1}, \param{str 2}, \param{id})}\\
+\begin{tabular}{ll}
+\param{nat 1}&	index of the origin judgment\\
+\param{nat 2}&	number of phantom steps\\
+\param{str 1}&	left label \emph{math-mode} \LaTeX\ code\\
+\param{str 2}&	right label \emph{math-mode} \LaTeX\ code\\
+\param{id}&	phantom steps path-style identifier ({\tt0}, {\tt1}, {\tt2},
+		{\tt3},	{\tt4}, {\tt5}, {\tt6} or {\tt\_})
+\end{tabular}\\[1ex]
+If \param{str 1} is a non-empty string then it is attached as a label to the
+left of the phantom steps path. The same way, if \param{str 2} is a non-empty
+string then it is attached as a label to the right of the phantom steps path.
+Both \param{str 1} and \param{str 2} may be non-empty strings.
+\begin{multicols}{2}
+\begin{Verbatim}
+beginfig(210)
+jgm 1 "aaa";
+jgm 2 "bbb";
+jgm 3 "ccc";
+nfr 1 () ("", _);
+nfr 2 () ("", _);
+nfr 3 (Mvd 1 (2, "d", "", 3), 2) ("", _);
+draw drv_tree;
+endfig;
+\end{Verbatim}
+\columnbreak
+
+\begin{gather*}
+\drv{drv-guide.210}
+\end{gather*}
+\end{multicols}
+%
+%
+\section{\texttt{drv} tunings\label{sec-tunings}}
+%
+%
+\texttt{drv} tuning macros set the parameters according to which derivation
+trees are typeset. All these macros have to be called outside figure
+environments (delimited by ``\texttt{beginfig(\param{index})},
+\texttt{endfig;}'' pairs).
+%
+%
+\begin{multicols}{2}
+\subsection{\texttt{drv\_font\_size}\label{sec-font-size}}
+%
+%
+\texttt{drv\_font\_size \param{str}}\\
+\begin{tabular}{ll}
+\param{str}&	\LaTeX\ font-size command\\
+&		\begin{tabular}{l}
+		\texttt{"\tbs{}tiny"}\\
+		\texttt{"\tbs{}scriptsize"}\\
+		\texttt{"\tbs{}footnotesize"}\\
+		\texttt{"\tbs{}small"}\\
+		\texttt{"\tbs{}normalsize"}\rlap{\quad\default}\\
+		\texttt{"\tbs{}large"}\\
+		\texttt{"\tbs{}Large"}\\
+		etc.
+		\end{tabular}
+\end{tabular}
+\columnbreak
+\begin{gather*}
+\texttt{"\tbs{}tiny"}\\
+\drv{drv-guide.220}\\
+\texttt{"\tbs{}small"}\\
+\drv{drv-guide.221}\\
+\texttt{"\tbs{}Large"}\\
+\drv{drv-guide.222}
+\end{gather*}
+\end{multicols}
+%
+%
+\subsection{\texttt{drv\_math\_style}\label{sec-math-style}}
+%
+%
+\texttt{drv\_math\_style (\param{id}, \param{str})}\\
+\begin{tabular}{ll}
+\param{id}&	component identifier ({\tt drv}, {\tt jdg}, {\tt ilb},
+		{\tt dlb} or {\tt plb})\\
+&		\begin{tabular}{lll}
+		{\tt drv}&	derivation trees&
+                  \default[ style: \texttt{"\tbs{}displaystyle"}]\\
+		{\tt jdg}&	judgments&
+                  \default[ style: \texttt{"\tbs{}textstyle"}]\\
+		{\tt ilb}&	inference labels&
+                  \default[ style: \texttt{"\tbs{}scriptstyle"}]\\
+		{\tt dlb}&	delimiter labels&
+                  \default[ style: \texttt{"\tbs{}textstyle"}]\\
+		{\tt plb}&	phantom steps labels&
+                  \default[ style: \texttt{"\tbs{}textstyle"}]
+		\end{tabular}\\
+\param{str}&	\LaTeX\ math-style command
+\end{tabular}\\[1ex]
+%
+%
+``\texttt{drv\_math\_style (drv, {\rm ---});}''
+\begin{gather*}
+\begin{array}{*{3}{@{}>{\centering}p{.33\textwidth}}@{}l@{}}
+\texttt{"\tbs{}displaystyle"}&
+\texttt{"\tbs{}textstyle"}&
+\texttt{"\tbs{}scriptstyle"}&\\[1ex]
+\drv{drv-guide.230}&
+\drv{drv-guide.231}&
+\drv{drv-guide.232}&
+\end{array}
+\end{gather*}
+%
+%
+``\texttt{drv\_math\_style (jdg, {\rm ---});}''
+\begin{gather*}
+\begin{array}{*{3}{@{}>{\centering}p{.33\textwidth}}@{}l@{}}
+\texttt{"\tbs{}displaystyle"}&
+\texttt{"\tbs{}textstyle"}&
+\texttt{"\tbs{}scriptstyle"}&\\[1ex]
+\drv{drv-guide.240}&
+\drv{drv-guide.241}&
+\drv{drv-guide.242}&
+\end{array}
+\end{gather*}
+%
+%
+``\texttt{drv\_math\_style (ilb, {\rm ---});}''
+\begin{gather*}
+\begin{array}{*{3}{@{}>{\centering}p{.33\textwidth}}@{}l@{}}
+\texttt{"\tbs{}textstyle"}&
+\texttt{"\tbs{}scriptstyle"}&
+\texttt{"\tbs{}scriptscriptstyle"}&\\[1ex]
+\drv{drv-guide.250}&
+\drv{drv-guide.251}&
+\drv{drv-guide.252}&
+\end{array}
+\end{gather*}
+Notice that the math-style of derivation trees determines the math-style of
+judgments (and of labels) in the same way as the math-style of fractions
+determines the math-style of numerators and denominators.
+%
+%
+\subsection{\texttt{drv\_scale}\label{sec-scale}}
+%
+%
+\texttt{drv\_scale (\param{id}, \param{float})}\\
+\begin{tabular}{ll}
+\param{id}&	scale identifier ({\tt clr}, {\tt prm}, {\tt jdg} or
+		{\tt ilb})\\
+&		\begin{tabular}{lll}
+		{\tt clr}&nice explanation soon
+		(see examples)&\default[ scale: 1]\\
+		{\tt prm}&nice explanation soon
+		(see examples)&\default[ scale: 1]\\
+		{\tt jdg}&nice explanation soon
+		(see examples)&\default[ scale: 1]\\
+		{\tt ilb}&nice explanation soon
+		(see examples)&\default[ scale: 1]
+		\end{tabular}\\
+\param{float}&scale value
+\end{tabular}\\[1ex]
+%
+%
+``\texttt{drv\_scale (clr, {\rm ---});}''
+\begin{gather*}
+\begin{array}{*{4}{@{}>{\centering}p{.25\textwidth}}@{}l@{}}
+\texttt{0}&
+\texttt{1}&
+\texttt{2.5}&
+\texttt{4}&\\[1ex]
+\drv{drv-guide.260}&
+\drv{drv-guide.261}&
+\drv{drv-guide.262}&
+\drv{drv-guide.263}&
+\end{array}
+\end{gather*}
+%
+%
+``\texttt{drv\_scale (prm, {\rm ---});}''
+\begin{gather*}
+\begin{array}{*{4}{@{}>{\centering}p{.25\textwidth}}@{}l@{}}
+\texttt{0}&
+\texttt{1}&
+\texttt{2.5}&
+\texttt{4}&\\[1ex]
+\drv{drv-guide.270}&
+\drv{drv-guide.271}&
+\drv{drv-guide.272}&
+\drv{drv-guide.273}&
+\end{array}
+\end{gather*}
+%
+%
+``\texttt{drv\_scale (jgm, {\rm ---});}''
+\begin{gather*}
+\begin{array}{*{4}{@{}>{\centering}p{.25\textwidth}}@{}l@{}}
+\texttt{0}&
+\texttt{1}&
+\texttt{2.5}&
+\texttt{4}&\\[1ex]
+\drv{drv-guide.280}&
+\drv{drv-guide.281}&
+\drv{drv-guide.282}&
+\drv{drv-guide.283}&
+\end{array}
+\end{gather*}
+%
+%
+``\texttt{drv\_scale (ilb, {\rm ---});}''
+\begin{gather*}
+\begin{array}{*{4}{@{}>{\centering}p{.25\textwidth}}@{}l@{}}
+\texttt{0}&
+\texttt{1}&
+\texttt{2.5}&
+\texttt{4}&\\[1ex]
+\drv{drv-guide.290}&
+\drv{drv-guide.291}&
+\drv{drv-guide.292}&
+\drv{drv-guide.293}&
+\end{array}
+\end{gather*}
+%
+%
+\subsection{\texttt{drv\_junction\_style}\label{sec-junction-style}}
+%
+%
+This macro sets the default way the premises of an inference have to be
+horizontally joined.\\[1ex]
+\texttt{drv\_junction\_style \param{id}}\\
+\begin{tabular}{ll}
+\param{id}&junction style identifier ({\tt 0}, {\tt 1} or {\tt 2})\\
+&		\begin{tabular}{ll}
+		{\tt 0}&``fully-interlacing''\\
+		{\tt 1}&``semi-interlacing''\quad\default\\
+		{\tt 2}&``non-interlacing''
+		\end{tabular}
+\end{tabular}
+\begin{gather*}
+\begin{array}{*{3}{@{}>{\centering}p{.33\textwidth}}@{}l@{}}
+\texttt{0}&
+\texttt{1}&
+\texttt{2}&\\[1ex]
+\drv{drv-guide.300}&
+\drv{drv-guide.301}&
+\drv{drv-guide.302}&
+\end{array}
+\end{gather*}
+%
+%
+\subsection{\texttt{drv\_alignment\_style}\label{sec-alignment-style}}
+%
+%
+This macro sets the default way a judgment has to be horizontally aligned
+relatively to its premises.\\[1ex]
+\texttt{drv\_alignment\_style \param{id}}\\
+\begin{tabular}{ll}
+\param{id}&	alignment style identifier ({\tt l}, {\tt c} or {\tt r})\\
+&		\begin{tabular}{ll}
+		{\tt l}&left\\
+		{\tt c}&centered\quad\default\\
+		{\tt r}&right
+		\end{tabular}
+\end{tabular}
+\begin{gather*}
+\begin{array}{*{3}{@{}>{\centering}p{.33\textwidth}}@{}l@{}}
+\texttt{l}&
+\texttt{c}&
+\texttt{r}&\\[1ex]
+\drv{drv-guide.310}&
+\drv{drv-guide.311}&
+\drv{drv-guide.312}&
+\end{array}
+\end{gather*}
+%
+%
+\subsection{\texttt{drv\_path\_style}\label{sec-path-style}}
+%
+%
+\texttt{drv\_path\_style (\param{id 1}, \param{id 2})}\\
+\begin{tabular}{ll}
+\param{id 1}&	path-type identifier ({\tt iln} or {\tt phm})\\
+&		\begin{tabular}{lll}
+		{\tt iln}	&inference lines&\default[ style: {\tt1}]\\
+		{\tt phm}	&phantom steps paths&\default[ style: {\tt3}]
+		\end{tabular}\\
+\param{id 2}&	path-style identifier ({\tt0}, {\tt1}, {\tt2}, {\tt3}, {\tt4},
+		{\tt5} or {\tt6})
+\end{tabular}
+%
+%
+\subsection{\texttt{drv\_labels\_position}\label{sec-labels-position}}
+%
+%
+\texttt{drv\_labels\_position (\param{id 1}, \param{id 2})}\\
+\begin{tabular}{ll}
+\param{id 1}&	label-type identifier ({\tt ilb}, {\tt plb} or {\tt dlb})\\
+&		\begin{tabular}{lll}
+		{\tt ilb}	&inference labels&
+		\default[ position: {\tt r}]\\
+		{\tt dlb}	&delimiter labels&
+		\default[ position: {\tt l}]\\
+		{\tt plb}	&phantom steps labels&
+		\default[ position: {\tt l}]
+		\end{tabular}\\
+\param{id 2}&	position identifier ({\tt l} or {\tt r})\\
+&		\begin{tabular}{ll}
+		{\tt l}&left\\
+		{\tt r}&right
+		\end{tabular}
+\end{tabular}\\[1ex]
+``\texttt{drv\_labels\_position (ilb, {\rm ---});}''
+\begin{gather*}
+\begin{array}{*{2}{@{}>{\centering}p{.24\textwidth}}@{}l@{}}
+{\tt l}&{\tt r}&\\[1ex]
+\drv{drv-guide.320}&
+\drv{drv-guide.321}&
+\end{array}
+\end{gather*}
+\enlargethispage{.25\baselineskip}%
+Setting a default position for delimiter labels (thus for delimiters) and for
+phantom steps labels may be useful in conjunction with declaration macros
+taking optional label arguments (see~\S~\ref{sec-labels}).
+%
+%
+\begin{multicols}{2}
+\subsection{\texttt{drv\_roots\_position}\label{sec-roots-position}}
+%
+%
+%\begin{multicols}{2}
+\texttt{drv\_roots\_position \param{id}}\\
+\begin{tabular}{ll}
+\param{id}&	position identifier ({\tt t} or {\tt b})\\
+&		\begin{tabular}{ll}
+		{\tt t}&top\\
+		{\tt b}&bottom\quad\default
+		\end{tabular}
+\end{tabular}
+\columnbreak
+
+\begin{gather*}
+\begin{array}{*{2}{@{}>{\centering}p{.24\textwidth}}@{}l@{}}
+\drv{drv-guide.330}&
+\drv{drv-guide.331}&
+\end{array}
+\end{gather*}
+\end{multicols}
+%
+%
+\subsection{\texttt{drv\_axis\_reference}\label{sec-axis-reference}}
+%
+%
+The baseline of derivation tree pictures is set in such a way that their
+math-axis coincides either with the axis of their root inference line or with
+the math-axis of their root judgment according to the default behaviour set by
+\texttt{drv\_axis\_reference}.\\[1ex]
+\texttt{drv\_axis\_reference \param{id}}\\
+\begin{tabular}{ll}
+\param{id}&	reference identifier ({\tt iln} or {\tt jdg})\\
+&		\begin{tabular}{lll}
+		{\tt iln}&root inference line axis&\default\\
+		{\tt jdg}&root judgment math-axis
+		\end{tabular}
+\end{tabular}
+\begin{gather*}
+\frac{\qquad}{}\textit{math axis}\frac{\qquad}{}
+\drv{drv-guide.340}\frac{\qquad}{}
+\drv{drv-guide.341}\frac{\qquad}{}
+\end{gather*}
+Notice that \texttt{drv\_axis\_reference} is irrelevant if you don't use the
+\texttt{\tbs{}drv} inclusion command (see \S~\ref{sec-inclusion}).
+%
+%
+\subsection{\texttt{drv\_left\_delimiter} \& \texttt{drv\_right\_delimiter}%
+\label{sec-delimiters}}
+%
+%
+\texttt{drv\_left\_delimiter \param{str}}\\
+\begin{tabular}{ll}
+\param{str}&	left delimiter math-mode \LaTeX\ code\\
+&		\begin{tabular}{llll}
+		\texttt{"("}&				$($\\
+		\texttt{"["}&				$[$\\
+		\texttt{"\tbs{}lbrace"}&	$\lbrace$&\default\\
+		\texttt{"\tbs{}langle"}&	$\langle$\\
+		etc.
+		\end{tabular}
+\end{tabular}\\[1ex]
+\texttt{drv\_right\_delimiter \param{str}}\\
+\begin{tabular}{ll}
+\param{str}&	right delimiter math-mode \LaTeX\ code\\
+&		\begin{tabular}{llll}
+		\texttt{")"}&				$)$\\
+		\texttt{"]"}&				$]$\\
+		\texttt{"\tbs{}rbrace"}&	$\rbrace$&\default\\
+		\texttt{"\tbs{}rangle"}&	$\rangle$\\
+		etc.
+		\end{tabular}
+\end{tabular}\\[1ex]
+``\texttt{drv\_left\_delimiter {\rm ---};}''
+\begin{gather*}
+\begin{array}{*{3}{@{}>{\centering}p{.33\textwidth}}@{}l@{}}
+\texttt{"("}&
+\texttt{"\tbs{}lfloor"}&
+\texttt{"."}&\\[1ex]
+\drv{drv-guide.350}&
+\drv{drv-guide.351}&
+\drv{drv-guide.352}&
+\end{array}
+\end{gather*}
+``\texttt{drv\_right\_delimiter {\rm ---};}''
+\begin{gather*}
+\begin{array}{*{3}{@{}>{\centering}p{.33\textwidth}}@{}l@{}}
+\texttt{"\tbs{}rangle"}&
+\texttt{"\tbs{}uparrow"}&
+\texttt{"."}&\\[1ex]
+\drv{drv-guide.360}&
+\drv{drv-guide.361}&
+\drv{drv-guide.362}&
+\end{array}
+\end{gather*}
+%
+%
+\subsection{\texttt{drv\_box\_mode}\label{sec-box-mode}}
+%
+%
+When in ``box mode'', derivation trees are typeset in such a way that all
+sub-trees behave as if they were enclosed within boxes (that is as if all
+premise indices were prefixed with \texttt{bxd},
+see~\S~\ref{sec-bxd-mvd}).\\[1ex]
+%
+%
+\texttt{drv\_box\_mode \param{id}}\\
+\begin{tabular}{ll}
+\param{id}&	status identifier ({\tt on} or {\tt off})\\
+&		\begin{tabular}{ll}
+		{\tt on}\\
+		{\tt off}&\default
+		\end{tabular}
+\end{tabular}
+\begin{gather*}
+\begin{array}{*{3}{@{}>{\centering}p{.33\textwidth}}@{}l@{}}
+\texttt{on}&
+typeset as&
+\texttt{off}&\\[1ex]
+\drv{drv-guide.370}&
+\drv{drv-guide.371}&
+\drv{drv-guide.372}&
+\end{array}
+\end{gather*}
+%
+%
+\subsection{\texttt{drv\_fraction\_mode}\label{sec-fraction-mode}}
+%
+%
+\nopagebreak\parbox{\textwidth}{\texttt{drv.mp} typesets derivation trees in
+such a way that: the distance from the axis of an inference line to the
+math-axis of a judgment above it is always the same (\texttt{num\_hg},
+see~\S~\ref{sec-components}); the distance from the axis of an inference line
+to the math-axis of a judgment below it is always the same (\texttt{den\_dp},
+see~\S~\ref{sec-components}). When in ``fraction mode'', if roots are at bottom
+then the height of leaf judgments above which there is no inference line is
+ignored (the depth of root judgments is always ignored); if roots are at top
+then the depth of leaf judgments below which there is no inference line is
+ignored (the height of root judgments is always ignored). This mode may cause
+overlaps when used in conjunction with
+interlacing junction-styles (\texttt{0} and \texttt{1}).}\\[1ex]
+\texttt{drv\_fraction\_mode \param{id}}\\
+\begin{tabular}{ll}
+\param{id}&	status identifier ({\tt on} or {\tt off})\\
+&		\begin{tabular}{ll}
+		{\tt on}&\default\\
+		{\tt off}
+		\end{tabular}
+\end{tabular}
+\begin{gather*}
+\begin{array}{*{3}{@{}>{\centering}p{.33\textwidth}}@{}l@{}}
+\texttt{on}&
+\texttt{off}&
+typeset as&\\[1ex]
+\drv{drv-guide.380}&
+\drv{drv-guide.381}&
+\drv{drv-guide.382}&
+\end{array}
+\end{gather*}
+%
+%
+\subsection{\texttt{drv\_proof\_mode}\label{sec-proof-mode}}
+%
+%
+\texttt{drv\_proof\_mode \param{id}}\\
+\begin{tabular}{ll}
+\param{id}&	status identifier ({\tt on} or {\tt off})\\
+&		\begin{tabular}{ll}
+		{\tt on}\\
+		{\tt off}&\default
+		\end{tabular}
+\end{tabular}
+\begin{gather*}
+\begin{array}{*{2}{@{}>{\centering}p{.5\textwidth}}@{}l@{}}
+\texttt{on}&
+\texttt{off}&\\[1ex]
+\drv{drv-guide.390}&
+\drv{drv-guide.391}&
+\end{array}\\[1ex]
+\end{gather*}
+Red numbers (resp. dots) refer to judgment indices (resp. central points,
+see~\S~\ref{sec-components}) while blue numbers (resp. dots) refer to
+sub-judgment indices (resp. central points, see~\S~\ref{sec-components}).
+%
+%
+\section{Pictures, bounding boxes and math-axis\label{sec-pictures}}
+%
+%
+\subsection{\texttt{drv\_freeze} \& \texttt{drv\_tree}}
+%
+%
+\texttt{drv.mp} composes derivation trees with respect to judgment and
+inference declarations only once the \texttt{drv\_freeze} macro is called.
+This is usually done by \texttt{drv\_tree} which is actually a macro that
+returns a picture. You may however call \texttt{drv\_freeze} yourself if you
+have no need for the whole derivation tree picture that \texttt{drv\_tree}
+would otherwise return (Section~\ref{sec-components} illustrates such a
+situation).
+
+\texttt{drv.mp} composes derivation trees essentially according to the
+algorithm for composing fractions described in Appendix~G of the {\TeX}book
+(see~\cite{jackowski06,knuth84}). In particular, \texttt{drv.mp} uses
+``\texttt{\tbs{}fontdimen}'' parameters so that the derivation tree pictures
+it generates should integrate smoothly within any document, whatever the fonts
+you use. As an example (when using the ``\texttt{drv\_scale (jgm, 0);}''
+tuning) \drv{drv-guide.400} should look the same as
+$\frac{\gamma}{\delta}$. The first fraction is composed by \texttt{drv.mp}
+while the second one is composed by the standard \texttt{\tbs{}frac}
+command.
+%
+%
+\subsection{\texttt{drv\_bbox}\label{sec-bbox}}
+%
+%
+\texttt{drv\_bbox \param{nat}}\\
+\begin{tabular}{ll}
+\param{nat}&	sub-tree root index
+\end{tabular}\\[1ex]
+``\texttt{drv\_bbox \param{nat}}'' returns a \MP\ path expression representing
+the bounding box of the sub-tree ending with the index \param{nat} judgment.
+\texttt{drv\_bbox} calls \texttt{drv\_freeze} if necessary.
+\begin{Verbatim}[commandchars=\\\{\}]
+beginfig(410)
+dcl 0 (1, 5) ("", _)      "a";
+\resplap{}dcl 0 (bxd 1, 5) ("", _)  "a";
+  dcl 1 (2, 3, 4) ("", _)   "b";
+    dcl 2 () ("", _)          "c";
+    dcl 3 () ("", _)          "d";
+    dcl 4 () ("", _)          "e";
+  dcl 5 () ("", _)          "f";
+fill drv_bbox 1 withcolor (255, 230, 205)/255; % rgb color
+draw drv_tree;
+endfig;
+\end{Verbatim}
+\begin{gather*}
+\drv{drv-guide.410}\quad\text{resp.}\quad\drv{drv-guide.411}
+\end{gather*}
+%
+%
+\subsection{\texttt{drv\_axis}\label{sec-axis}}
+%
+%
+\texttt{drv\_axis} allows you set the math-axis of a derivation tree with
+respect to a particular inference, judgment or sub-tree.\\[1ex]
+\texttt{drv\_axis (\param{id}, \param{nat})}\\
+\begin{tabular}{ll}
+\param{id}&	reference type identifier ({\tt iln}, {\tt jdg} or {\tt dlm})\\
+&		\begin{tabular}{ll}
+		{\tt iln}&inference line axis\\
+                {\tt jdg}&judgment math-axis\\
+                {\tt dlm}&delimiter axis
+                \end{tabular}\\
+\param{nat}&	reference index
+\end{tabular}
+\begin{Verbatim}[commandchars=\\\{\}]
+beginfig(420)
+Dcl 0 ( ) ("",   "", "", _) "a";
+Dcl 1 (0) ("", "{}", "", _) "b";
+draw drv_tree;
+drv_axis (iln, 0);
+\resplap{}drv_axis (jdg, 1);
+\resplap{}drv_axis (dlm, 1);
+endfig;
+\end{Verbatim}
+\begin{gather*}
+\drv{drv-guide.420}\frac{\qquad}{}\text{ resp. }\frac{\qquad}{}
+\drv{drv-guide.421}\frac{\qquad}{}\text{ resp. }\frac{\qquad}{}
+\drv{drv-guide.422}
+\end{gather*}
+Notice that \texttt{drv\_axis} is irrelevant if you don't use the
+\texttt{\tbs{}drv} inclusion command.% (see \S~\ref{sec-inclusion}).
+%
+%
+\section{Low level inference declaration macros\label{sec-low-level}}
+%
+%
+\subsection{\texttt{NFR}, \texttt{DCL} \& \texttt{MVD}\label{sec-NFR-DCL-MVD}}
+%
+%
+\paragraph{\texttt{NFR}}
+%
+%
+\enlargethispage{.05\baselineskip}%
+The \texttt{NFR} declaration macro is the lowest level one. It allows you to
+specify all the labels and styles of an inference.\\[1ex]
+\texttt{NFR
+\param{nat}
+(\param{nat\;list})
+(\param{str~1},\;\param{str~2},\;\param{str~3},\;\param{str~4})
+(\param{id~1},\;\param{id~2},\;\param{id~3})}
+\begin{tabular}{ll}
+\param{nat}&		inference index\\
+\param{nat list}&	list of premise indices\\
+\param{str 1}&		left inference label \emph{math-mode} \LaTeX\ code\\
+\param{str 2}&		right inference label \emph{math-mode} \LaTeX\ code\\
+\param{str 3}&		left delimiter label \emph{math-mode} \LaTeX\ code\\
+\param{str 4}&		right delimiter label \emph{math-mode} \LaTeX\ code\\
+\param{id 1}&		junction style identifier ({\tt0}, {\tt1}, {\tt2},
+			{\tt3} or {\tt\_})\\
+&			\begin{tabular}{ll}
+			{\tt0}&fully-interlacing\\
+			{\tt1}&semi-interlacing\\
+			{\tt2}&non-interlacing\\
+			{\tt3}&user specified (tricky,
+			see~\S~\ref{sec-user-specified})\\
+			{\tt\_}&default (set by \texttt{drv\_junction\_style},
+			see~\S~\ref{sec-junction-style})
+			\end{tabular}\\
+\param{id 2}&		alignment style identifier ({\tt l}, {\tt c}, {\tt r},
+			{\tt u} or {\tt\_})\\
+&			\begin{tabular}{ll}
+			{\tt l}&left\\
+			{\tt c}&centered\\
+			{\tt r}&right\\
+			{\tt u}&user specified (tricky,
+			see~\S~\ref{sec-user-specified})\\
+			{\tt\_}&default (set by \texttt{drv\_alignment\_style},
+			see~\S~\ref{sec-alignment-style})
+			\end{tabular}\\
+\param{id 3}&		inference line style identifier ({\tt0}, {\tt1},
+			{\tt2},	{\tt3}, {\tt4}, {\tt5}, {\tt6} or {\tt\_})
+\end{tabular}
+\begin{multicols}{3}
+\begin{Verbatim}
+beginfig(430)
+jgm 0 "a";
+NFR 0 () ("1", "2", "3", "4", _, _, _);
+draw drv_tree;
+endfig;
+\end{Verbatim}
+\columnbreak\ \columnbreak
+
+\begin{gather*}
+\drv{drv-guide.430}
+\end{gather*}
+\end{multicols}
+%
+%
+\paragraph{\texttt{DCL}}
+%
+%
+The \texttt{DCL} declaration macro is a shorthand for \texttt{jgm} and
+\texttt{NFR} in the same way as \texttt{dcl} is a shorthand for \texttt{jgm}
+and \texttt{nfr}.
+\begin{multicols}{3}
+\begin{Verbatim}
+beginfig(440)
+DCL 0 ()     ("1", "", "", "", _, _, _) "a";
+DCL 1 ()     ("", "2", "", "", _, _, _) "b";
+DCL 2 (0, 1) ("", "", "3", "", _, _, _) "c";
+DCL 3 (2)    ("", "", "", "4", _, _, _) "d";
+draw drv_tree;
+endfig;
+\end{Verbatim}
+\columnbreak\ \columnbreak
+
+\begin{gather*}
+\drv{drv-guide.440}
+\end{gather*}
+\end{multicols}
+%
+%
+\paragraph{\texttt{MVD}}
+%
+%
+The \texttt{MVD} macro is a generalization of \texttt{Mvd} that allows you to
+specify the alignment style of phantom inferences.\\[1ex]
+\texttt{MVD \param{nat 1}
+(\param{nat 2}, \param{str 1}, \param{str 2}, \param{id 1} \param{id 2})}\\
+\begin{tabular}{ll}
+\param{nat 1}&	index of the origin judgment\\
+\param{nat 2}&	number of phantom steps\\
+\param{str 1}&	left label \emph{math-mode} \LaTeX\ code\\
+\param{str 2}&	right label \emph{math-mode} \LaTeX\ code\\
+\param{id 1}&	alignment style identifier ({\tt l}, {\tt c}, {\tt r}, {\tt u}
+		or {\tt\_})\\
+\param{id 2}&	phantom steps path-style identifier ({\tt0}, {\tt1}, {\tt2},
+		{\tt3},	{\tt4}, {\tt5}, {\tt6} or {\tt\_})
+\end{tabular}
+\begin{multicols}{3}
+\begin{Verbatim}
+beginfig(450)
+jgm 0 "aaaaaa";
+jgm 1 "aaa";
+jgm 2 "a";
+jgm 3 "aaaaaaaaa";
+jgm 4 "a";
+nfr 0 () ("", _);
+NFR 1 () ("", "", "", "", _, _, _);
+nfr 2 (MVD 0 (2, "A", "", l, 3), 1) ("", _);
+nfr 3 () ("", _);
+nfr 4 (2, MVD 3 (5, "", "A", r, 4)) ("", _);
+draw drv_tree;
+endfig;
+\end{Verbatim}
+\columnbreak\ \columnbreak
+
+\begin{gather*}
+\drv{drv-guide.450}
+\end{gather*}
+\end{multicols}
+\pagebreak
+\begin{Verbatim}
+beginfig(460)
+jgm 0 "\textsc{Size matters -- Part 2}";
+jgm 1 "\text{Here is an even longer judgment"&
+      " that I don't want to shorten either.}";
+jgm 2 "\text{This time I'm pretty sure that the"&
+      " derivation tree won't fit on the page.}";
+jgm 3 "\text{It does! Amazing.}";
+nfr 0 () ("", 0);
+nfr 1 (0) ("", 1);
+nfr 2 () ("", 1);
+nfr 3 (MVD 1 (2, "", "", l, 3), 2) ("", 1);
+draw drv_tree;
+endfig;
+\end{Verbatim}
+\begin{gather*}
+\drv{drv-guide.460}
+\end{gather*}
+%
+%
+\subsection{Optional labels\label{sec-labels}}
+%
+%
+\paragraph{\texttt{NFR\_opt}}
+%
+%
+The \texttt{NFR\_opt} declaration macro is an alternative for \texttt{NFR}
+that lets you specify labels at your option.\\[1ex]
+\texttt{NFR\_opt
+\param{nat}
+(\param{nat list})
+(\param{str list 1})
+(\param{str list 2})
+(\param{id 1}, \param{id 2}, \param{id 3})}
+\begin{tabular}{ll}
+\param{nat}&		inference index\\
+\param{nat list}&	list of premise indices\\
+\param{str list 1}&	list of inference labels \emph{math-mode}
+			\LaTeX\ code\\
+\param{str list 2}&	list of delimiter labels \emph{math-mode}
+			\LaTeX\ code\\
+\param{id 1}&		junction style identifier ({\tt0}, {\tt1}, {\tt2},
+			{\tt3} or {\tt\_})\\
+\param{id 2}&		alignment style identifier ({\tt l}, {\tt c}, {\tt r},
+			{\tt u} or {\tt\_})\\
+\param{id 3}&		inference line style identifier ({\tt0}, {\tt1},
+			{\tt2},	{\tt3}, {\tt4}, {\tt5}, {\tt6} or {\tt\_})
+\end{tabular}\\[1ex]
+%
+%
+The list \param{str list 1} may contain zero, one or two
+strings specifying inference labels. If no label is specified then no label
+is attached to the inference line. If two labels are specified then the first
+one is attached to the left and the second one to the right. Finally, if one
+label only is specified then it is attached either to the left or to the right
+of the inference line depending on the default inference labels position set by
+\texttt{drv\_labels\_position} (see~\S~\ref{sec-labels-position}).
+
+The same way, \param{str list 2} may contain zero, one or two strings
+specifying delimiter labels. If one label only is specified then it is attached
+to a delimiter placed either to the left or to the right of the sub-tree ending
+with the index \param{nat} judgment depending on the default delimiter labels
+position set by \texttt{drv\_labels\_position}.
+
+As an example, ``\texttt{nfr \param{nat} (\param{nat list})
+(\param{str}, \param{id})}'' behaves exactly the same way as
+``\texttt{NFR\_opt \param{nat} (\param{nat list}) (\param{str}) ()
+(\_, \_, \param{id})}''.
+%
+%
+\paragraph{\texttt{DCL\_opt}}
+%
+%
+The \texttt{DCL\_opt} declaration macro is a shorthand for \texttt{jgm} and
+\texttt{NFR\_opt} in the same way as \texttt{DCL} is a shorthand for
+\texttt{jgm} and \texttt{NFR}.
+%
+%
+\paragraph{\texttt{MVD\_opt}}
+%
+%
+The \texttt{MVD\_opt} macro is an alternative for \texttt{MVD} that lets you
+specify labels at your option.\\[1ex]
+\texttt{MVD\_opt \param{nat 1} (\param{nat 2})
+(\param{str list}) (\param{id 1} \param{id 2})}\\
+\begin{tabular}{ll}
+\param{nat 1}&		index of the origin judgment\\
+\param{nat 2}&		number of phantom steps\\
+\param{str list}&	list of labels \emph{math-mode} \LaTeX\ code\\
+\param{id 1}&		alignment style identifier ({\tt l}, {\tt c}, {\tt r}
+			or {\tt u})\\
+\param{id 2}&		phantom steps path-style identifier ({\tt0}, {\tt1},
+			{\tt2},	{\tt3},	{\tt4}, {\tt5}, {\tt6} or {\tt\_})
+\end{tabular}\\[1ex]
+The list \param{str list} may contain zero, one or two
+strings specifying labels. If one label only is specified then it is attached
+either to the left or to the right of the phantom steps path depending on the
+default phantom steps labels position set by
+\texttt{drv\_labels\_position} (see~\S~\ref{sec-labels-position}).
+%
+%
+\subsection{User defined declaration macros (tricky)\label{sec-user-defined}}
+%
+%
+Here are the \MP\ headers for \texttt{NFR}, \texttt{MVD}, \texttt{NFR\_opt} and
+\texttt{MVD\_opt}.
+\begin{Verbatim}[commandchars=\\\{\}]
+NFR[](text PRM)(expr lilb, \!rilb, \!ldlb, \!rdlb)(suffix jsty, \!asty, \!isty)
+MVD[](expr num, lplb, rplb)(suffix asty, psty)
+NFR_opt[](text PRM)(text ILB)(text DLB)(suffix jsty, asty, isty)
+MVD_opt[](expr num)(text PLB)(suffix asty, psty)
+\end{Verbatim}
+``\texttt{[]}'' in the header of a macro indicates that this macro expects a
+numeric argument referred to as ``\texttt{@}'' in its body.
+``\texttt{text}'', ``\texttt{expr}'' and ``\texttt{suffix}'' specify argument
+types (see~\cite[Section 10]{hobby09}). You may use \texttt{NFR}, \texttt{MVD},
+\texttt{NFR\_opt} and \texttt{MVD\_opt} to define your own declaration macros.
+Here are possible definitions for \texttt{Nfr} and \texttt{Mvd}.
+\begin{Verbatim}
+vardef Nfr[](text PRM)(expr ilb, ldlb, rdlb)(suffix isty)=
+  NFR_opt[@](PRM)(ilb)(ldlb, rdlb)(_, _, isty);
+enddef;
+\end{Verbatim}
+\begin{Verbatim}
+vardef Mvd[](expr num, lplb, rplb)(suffix psty)=
+  MVD[@](num, lplb, rplb, _, psty) % Mvd returns an index, no `;'!
+enddef;
+\end{Verbatim}
+%
+%
+\section{Inside derivation trees\label{sec-inside}}
+%
+%
+\subsection{Components, distinguished points and
+dimensions\label{sec-components}}
+%
+%
+\paragraph{Components}
+%
+%
+Once \texttt{drv\_freeze} has been called, all the components of a derivation
+tree are accessible independently from each-other.
+%
+%
+\begin{Verbatim}
+beginfig(470) % components
+DCL 6 () ("", "", "", "", _, _, 0) "0";
+DCL 7 (6) ("(1)", "(2)", "(3)", "(4)", _, _, 1) "A", "B";
+drv_freeze; % usually called by drv_tree
+draw jdg[6];                        % judgment               0
+draw sbj[7][0] withcolor (0, 0, 1); % sub-judgment           A
+draw sbj[7][1] withcolor (0, 1, 0); % sub-judgment           B
+draw l_ilb[7]  withcolor (0, 1, 1); % left inference label  (1)
+draw r_ilb[7]  withcolor (1, 0, 0); % right inference label (2)
+draw l_dlb[7]  withcolor (1, 0, 1); % left delimiter label  (3)
+draw r_dlb[7]  withcolor (1, 1, 0); % right delimiter label (4)
+draw l_dlm[7];                      % left delimiter
+draw iln[7];                        % inference line
+draw r_dlm[7];                      % right delimiter
+endfig;
+\end{Verbatim}
+%\begin{gather*}
+%\drv{drv-guide.470}\qquad\drv{drv-guide.471}
+%\end{gather*}
+%
+%
+\paragraph{Distinguished points}
+%
+%
+Three distinguished points are associated with each component \param{cpn},
+namely \texttt{\param{cpn}.l}, \texttt{\param{cpn}.c} and
+\texttt{\param{cpn}.r} that lie respectively to the left, at the center and to
+the right of the component math-axis.
+\begin{gather*}
+\begin{array}{cc}
+\text{components}&\text{central points}\\[1ex]
+\drv{drv-guide.470}&\drv{drv-guide.471}
+\end{array}
+\end{gather*}
+%
+%
+\paragraph{Dimensions}
+%
+%
+Two dimensions are associated with each component \param{cpn}, a depth
+\texttt{\param{cpn}.dp} and a height \texttt{\param{cpn}.hg} that both are
+relative to the component math-axis. Two overall dimensions are associated with
+each derivation tree, \texttt{den\_dp} and \texttt{num\_hg}. The former
+refers to the depth of a judgment math-axis relatively to the axis of an
+inference line above it while the latter refers to the height of a judgment
+math-axis relatively to the axis of an inference line below it. Depths are
+negative while heights are positive.
+\begin{Verbatim}
+beginfig(470)
+dcl 0 ()  ("", 0) "\gamma";
+dcl 1 (0) ("", 1) "\delta";
+draw drv_tree;
+endfig;
+\end{Verbatim}
+(The picture below may look weird if you don't use scalable fonts.)
+\begin{gather*}
+\drv{drv-guide.480}
+\end{gather*}
+%
+%
+\subsection{\texttt{drv\_styled}\label{sec-styled}}
+%
+%
+\texttt{drv\_styled} allows you to draw \MP\ paths using \texttt{drv.mp}
+path-styles.\\[1ex]
+\texttt{\param{path} drv\_styled \param{id}}\\
+\begin{tabular}{ll}
+\param{path}&	\MP\ path expression\\
+\param{id}&	path style identifier ({\tt0}, {\tt1}, {\tt2}, {\tt3},
+		{\tt4}, {\tt5} or {\tt6})
+\end{tabular}
+\begin{Verbatim}
+beginfig(490)
+jgm 4 "A", "\vdash", "A";
+jgm 5 "B", "\vdash", "B";
+jgm 6 "A", ",", "A", "\multimap", "B", "\vdash", "B";
+jgm 7 "A", "\multimap", "B", "\vdash", "A", "\multimap", "B";
+nfr 4 () ("1", _);
+nfr 5 () ("1", _);
+nfr 6 (4, 5) ("\multimap_{L}", _);
+nfr 7 (6) ("\multimap_{R}", _);
+drv_freeze;
+draw (sbj[7][2].c shifted (0, -num_hg) ..
+      sbj[7][2].c {up} ..
+      sbj[6][4].c ..
+      sbj[5][0].c .. tension 1.05 ..
+      sbj[5][2].c ..
+      sbj[6][6].c ..
+      sbj[7][6].c {down} ..
+      sbj[7][6].c shifted (0, -num_hg))
+drv_styled 2 withcolor (1, 0, 0);
+draw drv_tree;
+endfig;
+\end{Verbatim}
+\begin{gather*}
+\drv{drv-guide.490}
+\end{gather*}
+%
+%
+\subsection{User specified junction \& alignment styles
+(tricky)\label{sec-user-specified}}
+%
+%
+\texttt{drp.mp} composes derivation trees by stating geometrical constraints to
+be solved by \MP. These constraints express how the components of a derivation
+tree must be arranged with respect to each-other. In the example about
+dimensions (see above), such a constraint could be that the vertical
+distance from
+\texttt{iln[1].c} to \texttt{jdg[0].c} has to be \texttt{num\_hg}, which could
+be \emph{stated} in the \MP\ syntax as
+``\texttt{ypart jdg[0].c=ypart iln[1].c+num\_hg}'' (this is \emph{not} an
+affectation).
+
+You can prevent \texttt{drp.mp} from stating \emph{horizontal}
+constraints about premises junction or judgments alignment by using the
+junction style~\texttt{3} or the alignment style~\texttt{u} of the \texttt{NFR}
+and \texttt{NFR\_opt} macros
+(see~\S~\ref{sec-NFR-DCL-MVD},~\ref{sec-labels}). In such cases, you have
+to state your own constraints. All the constraints related to a derivation tree
+must be stated \emph{before} \texttt{drv\_freeze} is called. \MP\ will complain
+if the constraints you state are insufficient, redundant or inconsistent.
+%
+%
+\paragraph{User specified junction style}
+%
+%
+The \emph{horizontal} constraints you state should express how the premises
+of the inference have to be joined.
+\begin{Verbatim}
+beginfig(500)
+jgm 0 "{\cdot}";
+jgm 1 "{\cdot}";
+jgm 2 "\text{You may check that the distance"&
+      " between the two dots above is 5 cm.}";
+NFR 0 () ("", "", "", "", _, _, _);
+NFR 1 () ("", "", "", "", _, _, _);
+NFR 2 (0, 1) ("", "", "", "", 3, _, _); % caution: 3
+xpart jdg[1].c=xpart jdg[0].c+5cm;
+draw drv_tree;
+endfig;
+\end{Verbatim}
+\begin{gather*}
+\drv{drv-guide.500}
+\end{gather*}
+%
+%
+\paragraph{User specified alignment style}
+The \emph{horizontal} constraints you state should express how the inferred
+judgment has to be aligned with respect to its premises.
+%
+%
+\begin{Verbatim}[commandchars=\\\{\}]
+beginfig(510)                                          % "\tbs{}vdash":
+jgm 0 "B, A, \tbs{}Gamma", "\tbs{
+}vdash", "C";                   % sbj[0][1]
+jgm 1 "A, \tbs{}Gamma", "\tbs{
+}vdash", "B\tbs{}multimap C";           % sbj[1][1]
+jgm 2 "\tbs{}Gamma", "\tbs{
+}vdash", "A\tbs{}multimap(B\tbs{}multimap C)";  % sbj[2][1]
+NFR_opt 0 () () () (_, _, 0);
+NFR_opt 1 (0) ("\tbs{}multimap_{R}") () (_, u, 1);            % caution: u
+NFR_opt 2 (1) ("\tbs{}multimap_{R}") () (_, u, 1);            % caution: u
+xpart sbj[1][1].c=xpart sbj[0][1].c;
+\resplap{}xpart sbj[1][1].l=xpart sbj[0][1].r;
+xpart sbj[2][1].c=xpart sbj[1][1].c;
+\resplap{}xpart sbj[2][1].l=xpart sbj[1][1].r;
+draw drv_tree;
+endfig;
+\end{Verbatim}
+\begin{gather*}
+\drv{drv-guide.510}\quad\text{resp.}\quad\drv{drv-guide.511}
+\end{gather*}
+%
+%
+\addcontentsline{toc}{section}{References}
+%
+%
+\begin{thebibliography}{1}
+\bibitem{hobby09}
+John~D. \textsc{Hobby}.
+\href{http://tug.org/docs/metapost/mpman.pdf}
+{\emph{A User's Manual for \MP}}, 2009
+\bibitem{jackowski06}
+Bogus{\l}aw \textsc{Jackowski}.
+\href{http://tug.org/TUGboat/Articles/tb27-1/tb86jackowski.pdf}
+{\emph{Appendix G illuminated}}. \emph{TUGboat}, 27(1):83--90, 2006.
+\bibitem{knuth84}
+Donald~E. \textsc{Knuth}.
+\emph{The {\TeX}book}.
+Addison-Wesley, 1984.
+\bibitem{restall06}
+Greg \textsc{Restall}.
+\href{http://consequently.org/papers/ptp.pdf}
+{\emph{Proof Theory and Philosophy}}. Book in progress, 2006.
+\bibitem{roegel02}
+Denis \textsc{Roegel}.
+\href{http://www.ctan.org/get/graphics/metapost/contrib/macros/%
+metaobj/doc/momanual.pdf}{\emph{The MetaObj tutorial and reference manual}},
+2002.
+\bibitem{lutz06}
+Lutz \textsc{Stra\ss{}burger}.
+\href{http://www.lix.polytechnique.fr/~lutz/papers/RR-6013.pdf}
+{\emph{Proof Nets and the Identity of Proofs}}. \textsc{Inria}, 2006.
+\end{thebibliography}
+%
+%
+\appendix
+\section{Debugging\label{sec-debugging}}
+%
+%
+Recall that you have to run ``\texttt{mpost \param{jobname}.mp}'' \emph{at
+least twice} (once more if you use sub-tree delimiters). If you get an error on
+the first run then it comes from the \texttt{drv.mp}/\MP\ code. If you get an
+error on the second run then it comes from the \LaTeX\ code.
+%
+%
+\paragraph{Error on the first run}
+\MP\ behaves essentially as \TeX/\LaTeX\ when it finds and error
+(see~\cite[Debugging]{hobby09}). It stops, ``explains'' the error in some way
+(look for the line starting with an exclamation mark \texttt{!}), shows some
+lines of context, and asks you what to do next (answer \texttt{h} to get some
+help or \texttt{x} to terminate the run). If you're lucky, the error comes from
+an inconsistency that \texttt{drv.mp} can detect. In such a case the
+explanation should be quite understandable.
+\begin{multicols}{2}
+\begin{Verbatim}[numbers=left,firstnumber=46]
+beginfig(520)
+jgm 0 "A\vdash B";
+jgm 1 "B\vdash C";
+jgm 2 "A\vdash C";
+jgm 3 "C\vdash D";
+jgm 4 "A\vdash D";
+nfr 0 () ("f", _);
+nfr 1 () ("g", _);
+nfr 2 (0, 1) ("\circ", _);
+nfr 3 () ("h", _);
+nfr 4 (0, 3) ("\circ", _);
+draw drv_tree;
+endfig;
+\end{Verbatim}
+\columnbreak
+\MP\ error message.
+\begin{Verbatim}[commandchars=\\\{\}]
+! drv (fig. 520): 0 has been used
+already as a premise index for
+inference declaration 2.
+\param{error context}
+l.56 nfr 4 (0, 3) ("{\tbs}circ", 1)
+                              ;
+?
+\end{Verbatim}
+\end{multicols}
+%
+%
+\paragraph{Error on the second run}
+\MP\ fails to preprocess the \LaTeX\ code in
+\texttt{\param{jobname}-delayed.mp} and suggests that you ``\texttt{see
+mpxerr.log}'' which is a regular \LaTeX\ log-file. This file shows you which
+part of the \LaTeX\ code is faulty but unfortunately not where to find it in
+\texttt{\param{jobname}.mp}.
+%
+%
+\section{Gallery\label{sec-gallery}}
+%
+%
+Here are the \texttt{drv.mp} version of a derivation tree found
+in~\cite[p.~57]{restall06} and an alternative for it (figures~530,~531).
+%
+%
+\begin{gather*}
+\drv{drv-guide.530}
+\end{gather*}
+\begin{gather*}
+\drv{drv-guide.531}
+\end{gather*}
+%
+%
+Here is the \texttt{drv.mp} version of a derivation tree found
+in~\cite[p.~86]{roegel02} (figure~540).
+\begin{gather*}
+\drv{drv-guide.540}
+\end{gather*}
+%
+%
+Here are the \texttt{drv.mp} versions of derivations trees found
+in~\cite[p.~50]{lutz06} (figures~550,~551).
+\begin{gather*}
+\drv{drv-guide.550}\quad\to\quad\drv{drv-guide.551}
+\end{gather*}
+%
+%
+Here is a continued fraction composed by \texttt{drv.mp} (figure~560).
+\begin{gather*}
+\drv{drv-guide.560}
+\end{gather*}
+%
+%
+\section{Standalone picture files\label{sec-standalone}}
+%
+%
+Given a PostScript file \texttt{\param{jobname}.\param{index}} generated by
+\MP, you may get a standalone \textsc{pdf} file (with embedded fonts)
+\texttt{\param{jobname}-\param{index}.pdf} by running
+\begin{center}
+\texttt{mptopdf \param{jobname}.\param{index}}
+\end{center}
+(\texttt{mptopdf} should be part of your \TeX\ distribution). Next you may
+get a standalone \textsc{ps} file \texttt{\param{jobname}-\param{index}.ps} by
+running
+\begin{center}
+\texttt{pdftops \param{jobname}-\param{index}.pdf}
+\end{center}
+(\texttt{pdftops} is part of the Xpdf software package). Finally you may get a
+standalone \emph{transparent} \textsc{png} file
+\texttt{\param{jobname}-\param{index}.png} by running
+\begin{center}
+\texttt{convert \param{jobname}-\param{index}.ps
+\param{jobname}-\param{index}.png}
+\end{center}
+(\texttt{convert} is part of the ImageMagick software package). Notice that you
+can run \texttt{convert} on \texttt{\param{jobname}-\param{index}.pdf} but then
+the \textsc{png} file you get is not transparent.
+%
+%
+\section{Related packages\label{sec-related}}
+%
+%
+\begin{itemize}
+\item
+\href{http://math.ucsd.edu/~sbuss/ResearchWeb/bussproofs/}
+{\texttt{bussproofs.sty}}
+(Samuel R. \textsc{Buss});
+\item
+\href{http://research.nii.ac.jp/~tatsuta/proof-sty.html}
+{\texttt{proof.sty}}
+(Makoto \textsc{Tatsuta});
+\item
+\href{http://www.paultaylor.eu/proofs/index.html}
+{\texttt{prooftree.sty}}
+(Paul \textsc{Taylor});
+\item
+the \texttt{Ptree} constructor from
+\href{http://tug.ctan.org/tex-archive/graphics/%
+metapost/contrib/macros/metaobj/}{\texttt{metaobj.mp}}
+(Denis \textsc{Roegel}, see~\cite{roegel02});
+\item
+\href{http://tug.ctan.org/tex-archive/macros/latex/contrib/semantic/}
+{\texttt{semantic.sty}}
+(Peter M\o ller \textsc{Neergaard} \& Arne John \textsc{Glenstrup});
+\item
+\href{http://alessio.guglielmi.name/res/vl/}
+{\texttt{virginialake.sty}}
+(Alessio \textsc{Guglielmi}).
+\end{itemize}
+Some of these are described on Peter \textsc{Smith}'s
+``\href{http://www.phil.cam.ac.uk/teaching_staff/Smith/logicmatters/%
+latexforlogician.html}{\LaTeX\ for Logicians}'' webpage.
+\end{document}
diff --git a/Master/texmf-dist/doc/metapost/drv/doc/drv.mp b/Master/texmf-dist/doc/metapost/drv/doc/drv.mp
new file mode 100644
index 00000000000..5eb38396144
--- /dev/null
+++ b/Master/texmf-dist/doc/metapost/drv/doc/drv.mp
@@ -0,0 +1,2245 @@
+%% drv.mp 0.93
+%% Copyright 2009 Laurent M\'ehats
+%
+% This work may be distributed and/or modified under the
+% conditions of the LaTeX Project Public License, either version 1.3
+% of this license or (at your option) any later version.
+% The latest version of this license is in
+%   http://www.latex-project.org/lppl.txt
+% and version 1.3 or later is part of all distributions of LaTeX
+% version 2005/12/01 or later.
+%
+% This work has the LPPL maintenance status `maintained'.
+%
+% The Current Maintainer of this work is Laurent M\'ehats.
+% <laurent.mehats@gmail.com>
+%
+% This work consists of the file drv.mp
+
+
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+%
+% User's macros summary
+%
+%
+% * Judgment & inference declarations
+% ===================================
+%
+%   jgm <nat> <str list>
+%	<nat>		judgment index
+%	<str list>	sub-judgments math-mode LaTeX code
+%
+%   nfr <nat> (<nat list>) (<str>, <id>)
+%	<nat>		inference index
+%	<nat list>	list of premise indices
+%	<str>		inference label math-mode LaTeX code
+%	<id>		inference line style identifier
+%			(0, 1, 2, 3, 4, 5, 6 or _)
+%			  0	none
+%			  1	simple
+%			  2	double
+%			  3	dotted
+%			  4	dashed
+%			  5	waved
+%			  6	TeX-dotted
+%			  _	default (set by drv_path_style)
+%
+%   mvd <nat 1> (<nat 2>, <id>)
+%	<nat 1>		index of the origin judgment
+%	<nat 2>		number of phantom steps
+%	<id>		phantom steps path-style identifier
+%			(0, 1, 2, 3, 4, 5, 6 or _)
+%
+%   Nfr <nat> (<nat list>) (<str 1>, <str 2>, <str 3>, <id>)
+%	<nat>		inference index
+%	<nat list>	list of premise indices
+%	<str 1>		inference label math-mode LaTeX code
+%	<str 2>		left delimiter label math-mode LaTeX code
+%	<str 3>		right delimiter label math-mode LaTeX code
+%	<id>		inference line style identifier
+%			(0, 1, 2, 3, 4, 5, 6 or _)
+%
+%   Mvd <nat 1> (<nat 2>, <str 1>, <str 2>, <id>)
+%	<nat 1>		index of the origin judgment
+%	<nat 2>		number of phantom steps
+%	<str 1>		left label math-mode LaTeX code
+%	<str 2>		right label math-mode LaTeX code
+%	<id>		phantom steps path-style identifier
+%			(0, 1, 2, 3, 4, 5, 6 or _)
+%
+%   NFR <nat> (<nat list>) (<str 1>, <str 2>, <str 3>, <str 4>)
+%     (<id 1>, <id 2>, <id 3>)
+%	<nat>		inference index
+%	<nat list>	list of premise indices
+%	<str 1>		left inference label math-mode LaTeX code
+%	<str 2>		right inference label math-mode LaTeX code
+%	<str 3>		left delimiter label math-mode LaTeX code
+%	<str 4>		right delimiter label math-mode LaTeX code
+%	<id 1>		junction style identifier (0, 1, 2, 3 or _)
+%			  0	fully-interlacing
+%			  1	semi-interlacing
+%			  2	non-interlacing
+%			  3	user specified (tricky)
+%			  _	default (set by drv_junction_style)
+%	<id 2>		alignment style identifier (l, c, r, u or _)
+%			  l	left
+%			  c	centered
+%			  r	right
+%			  u	user specified (tricky)
+%			  _	default (set by drv_alignment_style)
+%	<id 3>		inference line style identifier
+%			(0, 1, 2, 3, 4, 5, 6 or _)
+%
+%   MVD <nat 1> (<nat 2>, <str 1>, <str 2>, <id 1> <id 2>)
+%	<nat 1>		index of the origin judgment
+%	<nat 2>		number of phantom steps
+%	<str 1>		left label math-mode LaTeX code
+%	<str 2>		right label math-mode LaTeX code
+%	<id 1>		alignment style identifier (l, c, r, u or _)
+%	<id 2>		phantom steps path-style identifier
+%			(0, 1, 2, 3, 4, 5, 6 or _)
+%
+%   NFR_opt <nat> (<nat list>) (<str list 1>) (<str list 2>)
+%     (<id 1>, <id 2>, <id 3>)
+%	<nat>		inference index
+%	<nat list>	list of premise indices
+%	<str list 1>	list of inference labels math-mode LaTeX code
+%	<str list 2>	list of delimiter labels math-mode LaTeX code
+%	<id 1>		junction style identifier (0, 1, 2, 3 or _)
+%	<id 2>		alignment style identifier (l, c, r, u or _)
+%	<id 3>		inference line style identifier
+%			(0, 1, 2, 3, 4, 5, 6 or _)
+%
+%   MVD_opt <nat 1> (<nat 2>) (<str list>) (<id 1> <id 2>)
+%	<nat 1>		index of the origin judgment
+%	<nat 2>		number of phantom steps
+%	<str list>	list of labels math-mode LaTeX code
+%	<id 1>		alignment style identifier (l, c, r or u)
+%	<id 2>		phantom steps path-style identifier
+%			(0, 1, 2, 3, 4, 5, 6 or _)
+%
+% * Tunings
+% =========
+%
+%   drv_font_size <str>
+%	<str>		LaTeX font-size command
+%			  "\tiny"
+%			  "\scriptsize"
+%			  "\footnotesize"
+%			  "\small"
+%			  "\normalsize"
+%			  "\large"
+%			  "\Large"
+%			  etc.
+%
+%   drv_math_style (<id>, <str>)
+%	<id>		component identifier (drv, jdg, ilb, dlb or plb)
+%			  drv	derivation trees
+%			  jdg	judgments
+%			  ilb	inference labels
+%			  dlb	delimiter labels
+%			  plb	phantom steps labels
+%	<str>		LaTeX math-style command
+%
+%   drv_scale (<id>, <float>)
+%	<id>		scale identifier (clr, prm, jdg or ilb)
+%			  clr	nice explanation soon (see examples)
+%			  prm	nice explanation soon (see examples)
+%			  jdg	nice explanation soon (see examples)
+%			  ilb	nice explanation soon (see examples)
+%	<float>		scale value
+%
+%   drv_junction_style <id>
+%	<id>		junction style identifier (0, 1 or 2)
+%			  0	``fully-interlacing''
+%			  1	``semi-interlacing''
+%			  2	``non-interlacing''
+%
+%   drv_alignment_style <id>
+%	<id>		alignment style identifier (l, c or r)
+%			  l	left
+%			  c	centered
+%			  r	right
+%
+%   drv_path_style (<id 1>, <id 2>)
+%	<id 1>		path-type identifier (iln or phm)
+%			  iln	inference lines
+%			  phm	phantom steps paths
+%	<id 2>		path-style identifier (0, 1, 2, 3, 4, 5 or 6)
+%
+%   drv_labels_position (<id 1>, <id 2>)
+%	<id 1>		label-type identifier (ilb, plb or dlb)
+%			  ilb	inference labels
+%			  dlb	delimiter labels
+%			  plb	phantom steps labels
+%	<id 2>		position identifier (l or r)
+%			  l	left
+%			  r	right
+%
+%   drv_roots_position <id>
+%	<id>		position identifier (t or b)
+%			  t	top
+%			  b	bottom
+%
+%   drv_axis_reference <id>
+%	<id>		reference identifier (iln or jdg)
+%			  iln	root inference line axis
+%			  jdg	root judgment math-axis
+%
+%   drv_left_delimiter <str>
+%	<str>		left delimiter math-mode LaTeX code
+%			  "("	$($
+%			  "["	$[$
+%			  "\lbrace"	$\lbrace$
+%			  "\langle"	$\langle$
+%			  etc.
+%
+%   drv_right_delimiter <str>
+%	<str>		right delimiter math-mode LaTeX code
+%			  ")"
+%			  "]"
+%			  "\rbrace"
+%			  "\rangle"
+%			  etc.
+%
+%   drv_box_mode <id>
+%	<id>		status identifier (on or off)
+%			  on
+%			  off
+%
+%   drv_fraction_mode <id>
+%	<id>		status identifier (on or off)
+%			  on
+%			  off
+%
+%   drv_proof_mode <id>
+%	<id>		status identifier (on or off)
+%			  on
+%			  off
+%
+% * Derivation tree pictures
+% ==========================
+%
+%   drv_bbox <nat>
+%	<nat>		sub-tree root index
+%
+%   drv_axis (<id>, <nat>)
+%	<id>		reference type identifier (iln, jdg or dlm)
+%			  iln	inference line axis
+%			  jdg	judgment math-axis
+%			  dlm	delimiter axis
+%	<nat>		reference index
+%
+%   <path> drv_styled <id>
+%	<path>		MetaPost path expression
+%	<id>		path style identifier (0, 1, 2, 3, 4, 5 or 6)
+%
+
+
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+%
+% MetaPost messages formatting
+%
+
+% drv_format prevents messages from being automatically cut into lines every
+% 79 characters: if possible, a word which would otherwise be cut is 'pushed'
+% to the following line by inserting space characters before it.
+
+vardef drv_format (expr str, fst_len, nxt_len, dbl_pcs)=
+  % str: the message to be formatted
+  % fst_len: first line length
+  % nxt_len: following lines length
+  % dbl_pcs (boolean): occurrences of the percent character must be doubled
+  save str_len, sub_len, aux_len, chr_rnk, occ_num;
+  numeric str_len, sub_len, aux_len, chr_rnk, occ_num;
+  save aux_str, chr;
+  string aux_str, chr;
+  str_len:=length str;
+  sub_len:=0;
+  chr_rnk:=0;
+  occ_num:=0;
+  aux_len:=0;
+  aux_str:="";
+  forever:
+    exitif (chr_rnk=fst_len) or (chr_rnk=str_len);
+    chr:=substring (chr_rnk, chr_rnk+1) of str;
+    aux_str:=aux_str&chr;
+    if chr=" ":
+      sub_len:=chr_rnk+1;
+      aux_len:=sub_len+occ_num;
+    elseif (chr="%") and dbl_pcs:
+      aux_str:=aux_str&"%";
+      occ_num:=occ_num+1;
+    fi
+    chr_rnk:=chr_rnk+1;
+  endfor
+  if chr_rnk=fst_len:
+    begingroup
+      if sub_len=0:
+        sub_len:=fst_len;
+        aux_len:=sub_len+occ_num;
+      fi
+      substring (0, aux_len) of aux_str&
+        for idx=sub_len+1 upto fst_len:
+          " "&
+        endfor
+        drv_format (substring (sub_len, str_len) of str,
+          nxt_len, nxt_len, dbl_pcs)
+    endgroup
+  else:
+    aux_str
+  fi
+enddef;
+
+boolean drv_inside_fig;
+drv_inside_fig:=false;
+
+vardef drv_context=
+  "drv"&if drv_inside_fig: " (fig. "&decimal charcode&")"&fi ": "
+enddef;
+
+vardef drv_message expr str=
+  message drv_format (drv_context&str, 79, 79, false);
+enddef;
+
+vardef drv_errhelp expr str=
+  % Occurrences of the percent character must be doubled: errhelp makes single
+  % single occurrences behave as newline characters (this is inherited from
+  % MetaFont).
+  errhelp drv_format (str, 79, 79, true);
+enddef;
+
+vardef drv_errmessage expr str=
+  % errmessage inserts the 2-characters string  "! " before its argument.
+  % Hence 77 as a first line length argument.
+  errmessage drv_format (drv_context&str, 77, 79, false);
+enddef;
+
+
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+%
+% Delayed LaTeX processing
+%
+
+picture tex_pct[];
+string delayed_tex_file;
+delayed_tex_file:=jobname&"-delayed.mp";
+
+%
+% reading LaTeX picture definitions
+%
+
+boolean drv_nullpicture;
+drv_nullpicture:=true;
+
+string readfrom_str;
+readfrom_str:=readfrom delayed_tex_file;
+if readfrom_str<>EOF:
+  closefrom delayed_tex_file;
+  drv_message ("reading `"&delayed_tex_file&"' LateX picture definitions.");
+  batchmode;
+  scantokens ("input "&delayed_tex_file);
+  errorstopmode;
+  drv_message "done.";
+  drv_nullpicture:=false;
+fi
+
+%
+% copying LaTeX preamble
+%
+
+vardef drv_read (expr search_str) (suffix accum_str)=
+  save readfrom_str, readfrom_substr;
+  string readfrom_str, readfrom_substr;
+  accum_str:="";
+  forever:
+    readfrom_str:=readfrom jobname;
+    readfrom_substr:=substring (0, length search_str) of readfrom_str;
+    exitif (readfrom_substr=search_str) or (readfrom_str=EOF);
+    accum_str:=accum_str&readfrom_str&char(10);
+  endfor
+  if readfrom_str=EOF:
+    closefrom jobname;
+    drv_errhelp ("`"&jobname&".mp' should contain a line starting with "&
+      ditto&search_str&ditto&".");
+    drv_errmessage (ditto&search_str&ditto&" is missing");
+  fi
+enddef;
+
+string tex_preamble_str[];
+% tex_preamble_str[0] from "verbatimtex %&latex" to "\begin{document}"
+% tex_preamble_str[1] from "\begin{document}" to "etex;"
+
+drv_message ("reading `"&jobname&".mp' LateX preamble.");
+  drv_read ("verbatimtex %&latex", tex_preamble_str[0]);
+  drv_read ("\begin{document}", tex_preamble_str[0]);
+  drv_read ("etex;", tex_preamble_str[1]);
+  closefrom jobname;
+  write
+    "%"&char(10)&
+    "% AUTOMATICALLY GENERATED BY DRV.MP - DO NOT MODIFY."&char(10)&
+    "%"&char(10)&char(10)&
+    "verbatimtex %&latex"&char(10)&
+    tex_preamble_str[0]&
+    "\begin{document}"&char(10)&
+    tex_preamble_str[1]&
+    "etex;"
+  to delayed_tex_file;
+drv_message "done.";
+
+%
+% writing LaTeX picture definitions
+%
+
+numeric tex_pct_idx;
+tex_pct_idx:=0;
+
+% Math style indices: 0, 1, 2, 3
+string mth_sty_str[];
+mth_sty_str[0]:="\displaystyle";
+mth_sty_str[1]:="\textstyle";
+mth_sty_str[2]:="\scriptstyle";
+mth_sty_str[3]:="\scriptscriptstyle";
+
+string drv_fontsize;
+
+vardef drv_tex[] expr tex_str=
+  % @: math style index
+  % tex_str: math mode LaTeX code
+  save def_str, pct;
+  string def_str;
+  picture pct;
+  def_str:="btex{"&drv_fontsize&"$"&mth_sty_str[@]&"{}"&tex_str&"{}$}etex;";
+  write "tex_pct["&(decimal tex_pct_idx)&"]:="&def_str to delayed_tex_file;
+  pct:=
+    if known tex_pct[tex_pct_idx]:
+      tex_pct[tex_pct_idx]
+    else:
+      nullpicture
+    fi;
+  tex_pct_idx:=tex_pct_idx+1;
+  pct
+enddef;
+
+
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+%
+% MetaPost shorthands
+%
+
+vardef depth expr pct=
+  ypart llcorner pct
+enddef;
+
+vardef height expr pct=
+  ypart urcorner pct
+enddef;
+
+vardef width expr pct=
+  xpart urcorner pct-xpart llcorner pct
+enddef;
+
+
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+%
+% Font-specific parameters
+%
+
+%
+% em[s]		width of an m (s: mathstyle index)
+% ex[s]		height of an x
+% axis_hg[s]	height of the mathematical axis
+% num_bl_hg[s]	height of a numerator baseline w.r.t. the fraction bar axis
+% den_bl_dp[s]	depth of a denominator baseline w.r.t. the fraction bar axis
+% rul_thk[s]	default rule thickness
+%
+
+numeric em[], ex[], axis_hg[], num_bl_hg[], den_bl_dp[], rul_thk[];
+
+%
+% thn_sp[s]	thin space, usually 1em/6
+% med_sp[s]	medium space, usually 2em/9
+% thk_sp[s]	thick space, usually 5em/18
+%
+
+numeric thn_sp[], med_sp[], thk_sp[];
+
+%
+% pdt_hg[s]	height of a punctuation ldot
+% pdt_wd[s]	width of a punctuation ldot
+%
+
+numeric pdt_hg[], pdt_wd[];
+
+%
+% tt_dgt[s][i]	typewriter typeface digits (i ranges from 0 to 9)
+%
+
+picture tt_dgt[][];
+
+%
+% min_clr[s]	minimal clearance between a numerator
+%		or a denominator and the fraction bar
+% prm_skp[s]	<nice explanation>
+% jdg_skp[s]	<nice explanation>
+% ilb_skp[s]	<nice explanation>
+% plb_skp[s]	<nice explanation>
+%
+
+numeric min_clr[], prm_skp[], jdg_skp[], ilb_skp[], plb_skp[];
+
+vardef drv_fontdimen[] expr font=
+  save dim_pct;
+  picture dim_pct;
+  dim_pct:=drv_tex[0] ("\rule{\the\fontdimen"&(decimal @)&font&"}{0bp}");
+  width dim_pct
+enddef;
+
+vardef drv_font_size expr size_str=
+  save pdt_pct, sp_pct;
+  picture pdt_pct, sp_pct;
+  drv_fontsize:=size_str;
+  write char(10)&"% font-specific parameters ("&drv_fontsize&")"&char(10)
+    to delayed_tex_file;
+  ex[0]:=drv_fontdimen[5] "\textfont2";
+  ex[1]:=drv_fontdimen[5] "\textfont2";
+  ex[2]:=drv_fontdimen[5] "\scriptfont2";
+  ex[3]:=drv_fontdimen[5] "\scriptscriptfont2";
+  em[0]:=drv_fontdimen[6] "\textfont2";
+  em[1]:=drv_fontdimen[6] "\textfont2";
+  em[2]:=drv_fontdimen[6] "\scriptfont2";
+  em[3]:=drv_fontdimen[6] "\scriptscriptfont2";
+  rul_thk[0]:=drv_fontdimen[8] "\textfont3";
+  rul_thk[1]:=drv_fontdimen[8] "\textfont3";
+  rul_thk[2]:=drv_fontdimen[8] "\scriptfont3";
+  rul_thk[3]:=drv_fontdimen[8] "\scriptscriptfont3";
+  axis_hg[0]:=drv_fontdimen[22] "\textfont2";
+  axis_hg[1]:=drv_fontdimen[22] "\textfont2";
+  axis_hg[2]:=drv_fontdimen[22] "\scriptfont2";
+  axis_hg[3]:=drv_fontdimen[22] "\scriptscriptfont2";
+  num_bl_hg[0]:=(drv_fontdimen[8] "\textfont2")-axis_hg[0];
+  num_bl_hg[1]:=(drv_fontdimen[9] "\textfont2")-axis_hg[1];
+  num_bl_hg[2]:=(drv_fontdimen[9] "\scriptfont2")-axis_hg[2];
+  num_bl_hg[3]:=(drv_fontdimen[9] "\scriptscriptfont2")-axis_hg[3];
+  den_bl_dp[0]:=-(drv_fontdimen[11] "\textfont2")-axis_hg[0];
+  den_bl_dp[1]:=-(drv_fontdimen[12] "\textfont2")-axis_hg[1];
+  den_bl_dp[2]:=-(drv_fontdimen[12] "\scriptfont2")-axis_hg[2];
+  den_bl_dp[3]:=-(drv_fontdimen[12] "\scriptscriptfont2")-axis_hg[3];
+  min_clr[0]:=3*rul_thk[0]; % The TEXbook,
+  min_clr[1]:=1*rul_thk[1]; % Appendix G,
+  min_clr[2]:=1*rul_thk[2]; % Rule 15d.
+  min_clr[3]:=1*rul_thk[3]; %
+  for mth_sty:=0 upto 3:
+    sp_pct:=drv_tex[mth_sty] "\,";
+    thn_sp[mth_sty]:=width sp_pct;
+    sp_pct:=drv_tex[mth_sty] "\>";
+    med_sp[mth_sty]:=width sp_pct;
+    sp_pct:=drv_tex[mth_sty] "\;";
+    thk_sp[mth_sty]:=width sp_pct;
+    pdt_pct:=drv_tex[mth_sty] "\ldotp";
+    pdt_hg[mth_sty]:=height pdt_pct;
+    pdt_wd[mth_sty]:=width pdt_pct;
+    for dgt=0 upto 9:
+      tt_dgt[mth_sty][dgt]:=drv_tex[mth_sty] "\texttt{"&(decimal dgt)&"}";
+    endfor
+    prm_skp[mth_sty]:=3*med_sp[mth_sty]; % arbitrary
+    jdg_skp[mth_sty]:=thn_sp[mth_sty];   % arbitrary
+    ilb_skp[mth_sty]:=thn_sp[mth_sty];   % arbitrary
+    plb_skp[mth_sty]:=thk_sp[mth_sty];   % arbitrary
+  endfor
+enddef;
+
+
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+%
+% Math-related parameters & macros
+%
+
+%
+% Math styles
+% drv_sty		derivation trees
+% jdg_sty[drv_sty]	judgments
+% ilb_sty[drv_sty]	inference labels
+% dlb_sty[drv_sty]	delimiter labels
+% plb_sty[drv_sty]	phantom steps labels
+%
+
+numeric drv_sty, jdg_sty[], ilb_sty[], dlb_sty[], plb_sty[];
+
+%
+% Math-axis centered LaTeX pictures
+%
+
+vardef mth_tex[] expr tex_str=
+  (drv_tex[@] tex_str) shifted (0, -axis_hg[@])
+enddef;
+
+
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+%
+% drv-boxes
+%
+
+vardef drv_box text STR=
+  for str=STR:
+    expandafter picture scantokens str;
+    expandafter pair scantokens str.l;
+    expandafter pair scantokens str.c;
+    expandafter pair scantokens str.r;
+    expandafter numeric scantokens str.hg;
+    expandafter numeric scantokens str.dp;
+  endfor
+enddef;
+
+vardef box_init @# (expr pct)=
+  @#:=pct;
+  @#.r-@#.l=(width pct, 0);
+  @#.c=(@#.l+@#.r)/2;
+  @#.hg:=height pct;
+  @#.dp:=depth pct;
+enddef;
+
+vardef box_freeze @#=
+  @#:=@# shifted @#.l;
+enddef;
+
+
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+%
+% beginfig & endfig
+%
+
+%
+% drv_beginfig: figure initialization
+%
+
+pen drv_pen;
+
+vardef drv_beginfig=
+  %
+  % Judgments
+  %
+  % jdg[i]	judgment drv-box
+  % sbj_num[i]	number of sub-judgments
+  % sbj[i][j]	sub-judgment drv-box (j ranges from 0 to sbj_num[i]-1)
+  %
+  drv_box "jdg[]";
+  numeric sbj_num[];
+  drv_box "sbj[][]";
+  %
+  % Inferences
+  %
+  % prm_num[i]	number of premises
+  % prm[i][j]	premise index (j ranges from 0 to prm_num[i]-1)
+  % ccl[i]	conclusion index
+  % jct_sty[i]	junction style
+  % alg_sty[i]	alignment style
+  % iln_sty[i]	inference line style
+  % l_prm[i]	leftmost `graphical' premise index
+  % r_prm[i]	rightmost `graphical' premise index
+  %
+  numeric prm_num[], prm[][], ccl[];
+  numeric jct_sty[];
+  string alg_sty[];
+  numeric iln_sty[];
+  numeric l_prm[], r_prm[];
+  %
+  % imin_x[i]	inference minimal x
+  % l_dlb[i]	left delimiter label drv-box
+  % l_dlm[i]	left delimiter drv-box
+  % l_ilb[i]	left label drv-box
+  % iln[i]	inference line drv-box
+  % r_ilb[i]	right label drv-box
+  % r_dlm[i]	right delimiter drv-box
+  % r_dlb[i]	right delimiter label drv-box
+  % imax_x[i]	inference maximal x
+  %
+  numeric imin_x[];
+  drv_box "l_dlb[]", "l_dlm[]", "l_ilb[]";
+  drv_box "iln[]";
+  drv_box "r_ilb[]", "r_dlm[]", "r_dlb[]";
+  numeric imax_x[];
+  %
+  % Sub-trees
+  %
+  % smin_x[i]	sub-tree minimal x
+  % smax_x[i]	sub-tree maximal x
+  % smin_y[i]	sub-tree minimal y
+  % smax_y[i]	sub-tree maximal y
+  % boxed[i]	boolean
+  %
+  numeric smin_x[], smax_x[], smin_y[], smax_y[];
+  boolean boxed[];
+  %
+  % Pen initialization
+  %
+  drv_pen:=pencircle scaled rul_thk[drv_sty];
+  %
+  % num_hg	height of a numerator axis w.r.t. the fraction bar axis
+  % den_dp	depth of a denominator axis w.r.t. the fraction bar axis
+  % iln_hg[s]	height of a style s inference line
+  % iln_dp[s]	depth of a style s inference line
+  %
+  numeric num_hg, den_dp, iln_hg[], iln_dp[];
+  num_hg:=num_bl_hg[drv_sty]+axis_hg[jdg_sty[drv_sty]];
+  den_dp:=den_bl_dp[drv_sty]+axis_hg[jdg_sty[drv_sty]];
+  picture iln_pct;
+  for sty=0 upto 6:
+    iln_pct:=((0, 0)--(10, 0)) drv_styled sty;
+    iln_hg[sty]:=height iln_pct;
+    iln_dp[sty]:=depth iln_pct;
+  endfor
+  %
+  % Derivation trees
+  %
+  % root_num	number of roots
+  % root[i]	root index (i ranges from 0 to root_num-1)
+  % drv_built	boolean
+  % drv_frozen	boolean
+  %
+  numeric root_num, root[];
+  boolean drv_checked, drv_built, drv_frozen;
+  root_num:=0;
+  drv_checked:=false;
+  drv_built:=false;
+  drv_frozen:=false;
+  %
+  % Phantom steps
+  %
+  % phm_idx	phantom inferences index
+  % src[i]	base phantom judgment index (in case of an origin judgment)
+  % tgt[i]	origin judgment index (in case of a base phantom judgment)
+  % phm_sty[i]	phantom steps style
+  % l_plb[i]	left phantom steps label drv-box (in case of a base
+  %		phantom judgment)
+  % phm[i]	phantom steps drv-box (in case of a base phantom
+  %		judgment)
+  % r_plb[i]	right phantom steps label drv-box (in case of a base
+  %		phantom judgment)
+  %
+  numeric phm_idx, src[], tgt[], phm_sty[];
+  phm_idx:=0;
+  drv_box "l_plb[]", "phm[]", "r_plb[]";
+  %
+  % Proof pictures
+  %
+  % jdg_prf[i]		judgment index drv-box
+  % sbj_prf[i][j]	sub-judgment index drv-box (j ranges from 0 to
+  %			sbj_num[i]-1)
+  %
+  drv_box "jdg_prf[]", "sbj_prf[][]";
+  %
+  % Info
+  %
+  write char(10)&"% fig. "&(decimal charcode)&char(10) to delayed_tex_file;
+  drv_inside_fig:=true; % context: inside a figure
+enddef;
+
+extra_beginfig:=extra_beginfig&"drv_beginfig;";
+
+%
+% drv_endfig: proof-file generation
+%
+
+string proof_file;
+proof_file:=jobname&"-proof.tex";
+
+% TODO: taking outputtemplate into account.
+vardef output_file[]=
+  jobname&"."&(decimal @)
+enddef;
+
+string buf_str;
+buf_str:=
+  "%"&char(10)&
+  "% AUTOMATICALLY GENERATED BY DRV.MP."&char(10)&
+  "%"&char(10)&char(10)&
+  tex_preamble_str[0]&
+  "\usepackage{graphicx}"&char(10)&
+  "\makeatletter"&char(10)&
+  "\def\Gin@def@bp#1\relax#2#3{\gdef#2{#3}}"&char(10)&
+  "\newsavebox{\graphicsbox}"&char(10)&
+  "\newcommand*{\drv}[1]{%"&char(10)&
+  "\sbox{\graphicsbox}{\includegraphics{#1}}%"&char(10)&
+  "\raisebox{\Gin@lly bp}%"&char(10)&
+  "{\usebox{\graphicsbox}}}"&char(10)&
+  "\makeatother"&char(10)&char(10)&
+  "\newcount\h"&char(10)&
+  "\newcount\m"&char(10)&
+  "\h=\time"&char(10)&
+  "\divide\h 60"&char(10)&
+  "\m=-\h"&char(10)&
+  "\multiply\m 60"&char(10)&
+  "\advance\m\time"&char(10)&
+  "\def\hm{\number\h:\ifnum\m<10{}0\fi\number\m}"&char(10)&char(10)&
+  "\newcommand{\mathaxis}{\frac{\quad}{}}"&char(10)&char(10)&
+  "\begin{document}"&char(10)&
+  tex_preamble_str[1]&
+  "\noindent\today\ at \hm\medskip"&char(10)&char(10)&"\noindent";
+
+vardef drv_endfig=
+  drv_inside_fig:=false;   % context: outside a figure
+  buf_str:=buf_str&char(10)&
+  "\texttt{"&output_file[charcode]&"}"&char(10)&
+  "  (\verb+"&drv_fontsize&"+, \verb+"&(mth_sty_str[drv_sty])&"+)"&char(10)&
+  "    {"&drv_fontsize&char(10)&
+  "      \["&(mth_sty_str[drv_sty])&char(10)&
+  "        \mathaxis\drv{"&output_file[charcode]&"}\mathaxis"&char(10)&
+  "      \]}\\";
+  write EOF to proof_file; % erases the previous content
+  write buf_str&char(10)&"\end{document}" to proof_file;
+  write EOF to proof_file;
+  if drv_nullpicture:
+    draw btex{\tt drv}: run {\tt mpost} again.etex withcolor (1, 0, 0);
+  fi
+enddef;
+
+extra_endfig:="drv_endfig;"&extra_endfig;
+
+
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+%
+% Judgment declarations
+%
+
+vardef jgm[] text SUB=
+  % @: judgment index
+  % SUB: list of `sub-judgments' (pictures or strings)
+  if @<0:
+    drv_errhelp "An judgment index can not be negative.";
+    drv_errmessage (decimal @)&" is negative";
+  elseif known jdg[@]:
+    drv_errhelp "An index can be used only once to declare a judgment.";
+    drv_errmessage (decimal @)&" has been used already as a judgment index";
+  else:
+    save jdg_pct, sbj_pct, jdg_wd, sbj_rnk;
+    picture jdg_pct, sbj_pct;
+    numeric jdg_wd, sbj_rnk;
+    jdg_pct:=nullpicture;
+    jdg_wd:=0;
+    sbj_rnk:=0;
+    for sub=SUB:
+      sbj_pct:=
+        if picture sub:
+          sub
+        elseif sub<>"":
+          mth_tex[jdg_sty[drv_sty]] sub
+        else:
+          nullpicture
+        fi;
+      box_init sbj[@][sbj_rnk] (sbj_pct);
+      if sbj_rnk>0:
+        sbj[@][sbj_rnk-1].r=sbj[@][sbj_rnk].l;
+      fi
+      addto jdg_pct also sbj_pct shifted (jdg_wd, 0);
+      jdg_wd:=width jdg_pct;
+      sbj_rnk:=sbj_rnk+1;
+    endfor
+    sbj_num[@]:=sbj_rnk;
+    box_init jdg[@] (jdg_pct);
+    if sbj_num[@]>0:
+      jdg[@].l=sbj[@][0].l;
+      jdg[@].r=sbj[@][sbj_num[@]-1].r;
+    fi
+  fi
+enddef;
+
+
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+%
+% Inference declarations
+%
+
+vardef check_junction_style (suffix sty_sfx) (expr default)=
+  save sty_str;
+  string sty_str;
+  sty_str:=str sty_sfx;
+  if (sty_str="0")
+  or (sty_str="1")
+  or (sty_str="2")
+  or (sty_str="3"):
+    sty_sfx
+  elseif (sty_str="_"):
+    default
+  else:
+    begingroup
+      drv_errhelp "Valid identifiers are"&
+        " 0 (fully-interlacing),"&
+        " 1 (semi-interlacing),"&
+        " 2 (non-interlacing),"&
+        " 3 (user specified) and"&
+        " _ (default).";
+      drv_errmessage sty_str&" is not a valid junction style identifier";
+      default
+    endgroup
+  fi
+enddef;
+
+vardef check_alignment_style (suffix sty_sfx) (expr default)=
+  save sty_str;
+  string sty_str;
+  sty_str:=str sty_sfx;
+  if (sty_str="l")
+  or (sty_str="c")
+  or (sty_str="r")
+  or (sty_str="u"):
+    sty_str
+  elseif (sty_str="_"):
+    default
+  else:
+    begingroup
+      drv_errhelp "Valid identifiers are"&
+        " l (none),"&
+        " c (simple),"&
+        " r (double),"&
+        " u (dotted) and"&
+        " _ (default).";
+      drv_errmessage sty_str&" is not a valid alignment style identifier";
+      default
+    endgroup
+  fi
+enddef;
+
+vardef check_path_style (suffix sty_sfx) (expr default)=
+  save sty_str;
+  string sty_str;
+  sty_str:=str sty_sfx;
+  if (sty_str="0")
+  or (sty_str="1")
+  or (sty_str="2")
+  or (sty_str="3")
+  or (sty_str="4")
+  or (sty_str="5")
+  or (sty_str="6"):
+    sty_sfx
+  elseif (sty_str="_"):
+    default
+  else:
+    begingroup
+      drv_errhelp "Valid identifiers are"&
+        " 0 (none),"&
+        " 1 (simple),"&
+        " 2 (double),"&
+        " 3 (dotted),"&
+        " 4 (dashed),"&
+        " 5 (waved),"&
+        " 6 (TeX-dotted) and"&
+        " _ (default).";
+      drv_errmessage sty_str&" is not a valid path style identifier";
+      default
+    endgroup
+  fi
+enddef;
+
+vardef opt_init[] @# expr arg=
+  if picture arg:
+    if arg<>nullpicture:
+      box_init @# (arg);
+    fi
+  elseif arg<>"":
+    box_init @# (mth_tex[@] arg);
+  fi
+enddef;
+
+vardef NFR[] (text PRM) (expr lilb, rilb, ldlb, rdlb)
+  (suffix j_sty, a_sty, i_sty)=
+  %
+  % @: inference index
+  %
+  if known prm_num[@]:
+    drv_errhelp "An index can be used only once to declare an inference.";
+    drv_errmessage (decimal @)&" has been used already as an inference index";
+  else:
+    %
+    % PRM: list of premise indices
+    %
+    save prm_rnk;
+    numeric prm_rnk;
+    prm_rnk:=0;
+    for prm_idx=PRM:
+      if prm_idx=@:
+        drv_errhelp "An inference index can not be used"&
+          " as one of its own premise indices.";
+        drv_errmessage "the inference index "&(decimal prm_idx)&
+          " is used as one of its own premise indices";
+      elseif known ccl[prm_idx]:
+        drv_errhelp "An index can be used only once as a premise index.";
+        drv_errmessage (decimal prm_idx)&" has been used already as a"&
+          " premise index for inference declaration "&(decimal ccl[prm_idx]);
+      else:
+        if known prm_num[prm_idx]:
+          %
+          % roots list update
+          %
+          save root_idx;
+          numeric root_idx;
+          root_idx:=0;
+          forever:
+            exitif root[root_idx]=prm_idx;
+            root_idx:=root_idx+1;
+          endfor
+          forever:
+            exitif root_idx=root_num-1;
+            root[root_idx]:=root[root_idx+1];
+            root_idx:=root_idx+1;
+          endfor
+          root_num:=root_num-1;
+        fi
+        ccl[prm_idx]:=@;
+        prm[@][prm_rnk]:=prm_idx;
+        prm_rnk:=prm_rnk+1;
+      fi
+    endfor
+    prm_num[@]:=prm_rnk;
+    if known ccl[@]:
+      %
+      % cycle detection
+      %
+      save ccl_idx, ccl_str;
+      numeric ccl_idx;
+      string ccl_str;
+      ccl_idx:=@;
+      ccl_str:=decimal ccl_idx;
+      forever:
+        ccl_idx:=ccl[ccl_idx];
+        if ccl_idx>=0:
+          ccl_str:=(decimal ccl_idx)&", "&ccl_str;
+        fi
+        exitif (unknown ccl[ccl_idx]) or (ccl_idx=@);
+      endfor
+      if ccl_idx=@:
+        drv_errhelp  "Inferences declarations can not be cyclic.";
+        drv_errmessage "inference declaration "&(decimal @)&" creates a"&
+          " cycle of inferences (indices "&ccl_str&" from conclusions to"&
+          " premises)";
+      fi
+    else:
+      root[root_num]:=@;
+      root_num:=root_num+1;
+    fi
+    %
+    % lilb, rilb: inference labels
+    %
+    opt_init[ilb_sty[drv_sty]] l_ilb[@] lilb;
+    opt_init[ilb_sty[drv_sty]] r_ilb[@] rilb;
+    %
+    % ldlb, rdlb: delimiter labels
+    %
+    opt_init[dlb_sty[drv_sty]] l_dlb[@] ldlb;
+    opt_init[dlb_sty[drv_sty]] r_dlb[@] rdlb;
+    %
+    % j_sty, a_sty and i_sty: junction, alignment and inference styles
+    %
+    jct_sty[@]:=check_junction_style (j_sty, drv_jct_sty);
+    alg_sty[@]:=check_alignment_style (a_sty, drv_alg_sty);
+    iln_sty[@]:=check_path_style (i_sty, drv_iln_sty);
+    if drv_boxmode_on:
+      boxed[@]:=true;
+    fi
+  fi
+enddef;
+
+vardef DCL[] (text PRM) (expr lilb, rilb, ldlb, rdlb)
+  (suffix j_sty, a_sty, i_sty) text SUB=
+    NFR[@] (PRM) (lilb, rilb, ldlb, rdlb, j_sty, a_sty, i_sty);
+    jgm[@] SUB;
+enddef;
+
+vardef MVD[] (expr inf_num, lplb, rplb) (suffix a_sty, p_sty)=
+  if inf_num<1:
+    drv_errhelp "The minimal value is 1.";
+    drv_errmessage (decimal inf_num)&" is not a valid number of inference"&
+      " steps";
+  else:
+    save aux_idx, aux_sty, phm_jdg;
+    numeric aux_idx, aux_sty;
+    picture phm_jdg;
+    aux_sty:=check_path_style (p_sty, drv_phm_sty);
+    phm_jdg:=nullpicture;
+    setbounds phm_jdg to (0, 0)--(iln_hg[aux_sty]-iln_dp[aux_sty], 0)--cycle;
+    aux_idx:=@;
+    for i=1 upto inf_num:
+      phm_idx:=phm_idx-1;
+      box_init jdg[phm_idx] (phm_jdg);
+      sbj_num[phm_idx]:=0;
+      NFR[phm_idx] (aux_idx) ("", "", "", "", 0, a_sty, 0);
+      aux_idx:=phm_idx;
+    endfor
+    src[@]:=phm_idx;
+    tgt[phm_idx]:=@;
+    phm_sty[phm_idx]:=aux_sty;
+    %
+    % lplb, rplb: phantom steps labels
+    %
+    opt_init[plb_sty[drv_sty]] l_plb[phm_idx] lplb;
+    opt_init[plb_sty[drv_sty]] r_plb[phm_idx] rplb;
+    phm_idx
+  fi
+enddef;
+
+vardef bxd[]=
+  boxed[@]:=true;
+  @
+enddef;
+
+%
+% Optional labels & shorthands
+%
+
+numeric drv_jct_sty;	% default junction style
+string  drv_alg_sty;	% default junction style
+numeric drv_iln_sty;	% default inference line path-style
+numeric drv_phm_sty;	% default phantom steps path-style
+
+boolean drv_left_ilb;	% inference labels on the left
+boolean drv_left_dlb;	% delimiter labels (hence delimiters) on the left
+boolean drv_left_plb;	% phantom steps labels on the left
+
+vardef arg_type expr arg=
+  if picture arg:
+    "picture"
+  else:
+    "string"
+  fi
+enddef;
+
+vardef opt_lbls @# (text LBL) expr left_lbls=
+  save lbl_num, fst_lbl, snd_lbl;
+  numeric lbl_num;
+  lbl_num:=0;
+  for lbl=LBL:
+    if lbl_num=0:
+      scantokens (arg_type lbl) fst_lbl;
+      fst_lbl:=lbl;
+    elseif lbl_num=1:
+      scantokens (arg_type lbl) snd_lbl;
+      snd_lbl:=lbl;
+    else:
+      drv_errhelp "At most two labels can be specified:"&
+        " a left one and a right one.";
+      drv_errmessage "more than two labels have been specified";
+    fi
+    lbl_num:=lbl_num+1;
+  endfor
+  if lbl_num=0:
+    string @#.l;
+    string @#.r;
+    @#.l:="";
+    @#.r:="";
+  elseif lbl_num=1:
+    if left_lbls:
+      scantokens (arg_type fst_lbl) @#.l;
+      string @#.r;
+      @#.l:=fst_lbl;
+      @#.r:="";
+    else:
+      string @#.l;
+      scantokens (arg_type fst_lbl) @#.r;
+      @#.l:="";
+      @#.r:=fst_lbl;
+    fi
+  else:
+    scantokens (arg_type fst_lbl) @#.l;
+    scantokens (arg_type snd_lbl) @#.r;
+    @#.l:=fst_lbl;
+    @#.r:=snd_lbl;
+  fi
+enddef;
+
+vardef NFR_opt[] (text PRM) (text ILB) (text DLB)
+  (suffix j_sty, a_sty, i_sty)=
+    opt_lbls ilb (ILB) drv_left_ilb;
+    opt_lbls dlb (DLB) drv_left_dlb;
+    NFR[@] (PRM) (ilb.l, ilb.r, dlb.l, dlb.r, j_sty, a_sty, i_sty);
+enddef;
+
+vardef DCL_opt[] (text PRM) (text ILB) (text DLB)
+  (suffix j_sty, a_sty, i_sty) text SUB=
+    NFR_opt[@] (PRM) (ILB) (DLB) (j_sty, a_sty, i_sty);
+    jgm[@] SUB;
+enddef;
+
+vardef MVD_opt[] (expr inf_num) (text PLB) (suffix a_sty, p_sty)=
+  opt_lbls plb (PLB) drv_left_plb;
+  MVD[@] (inf_num, plb.l, plb.r, a_sty, p_sty)
+enddef;
+
+% Nfr, Dcl & Mvd
+
+vardef Nfr[] (text PRM) (expr ilb, ldlb, rdlb) (suffix i_sty)=
+  NFR_opt[@] (PRM) (ilb) (ldlb, rdlb) (_, _, i_sty);
+enddef;
+
+vardef Dcl[] (text PRM) (expr ilb, ldlb, rdlb) (suffix i_sty) text SUB=
+  Nfr[@] (PRM) (ilb, ldlb, rdlb, i_sty);
+  jgm[@] SUB;
+enddef;
+
+vardef Mvd[] (expr inf_num, lplb, rplb) (suffix p_sty)=
+  MVD[@] (inf_num, lplb, rplb, _, p_sty)
+enddef;
+
+% nfr, dcl & mvd
+
+vardef nfr[] (text PRM) (expr ilb) (suffix i_sty)=
+  NFR_opt[@] (PRM) (ilb) () (_, _, i_sty);
+enddef;
+
+vardef dcl[] (text PRM) (expr ilb) (suffix i_sty) text SUB=
+  nfr[@] (PRM) (ilb, i_sty);
+  jgm[@] SUB;
+enddef;
+
+vardef mvd[] (expr inf_num) (suffix p_sty)=
+  MVD_opt[@] (inf_num) () (_, p_sty)
+enddef;
+
+
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+%
+% Pictured paths
+%
+
+vardef dotted_aux (expr pth, dot_wd, dots_dist)=
+  save pth_len, pct;
+  numeric pth_len;
+  picture pct;
+  pth_len:=arclength pth;
+  pct:=nullpicture;
+  if dots_dist>0:
+    stp_num:=round ((pth_len-dot_wd)/dots_dist);
+    if stp_num>0:
+      stp_len:=(pth_len-dot_wd)/stp_num;
+      addto pct doublepath pth dashed dashpattern (on 0 off stp_len)
+        shifted (dot_wd/2, 0) withpen pencircle scaled dot_wd;
+    fi
+  fi
+  pct
+enddef;
+
+primarydef pth dotted wd_dist=
+  dotted_aux(pth, xpart wd_dist, ypart wd_dist)
+enddef;
+
+vardef expanded_aux (expr pth, scl, dir, stp_len)=
+  save pth_len, aux_len;
+  numeric pth_len, aux_len;
+  pth_len:=arclength pth;
+  if (stp_len>0) and (pth_len>stp_len):
+    aux_len:=pth_len/(pth_len div stp_len);
+    point arctime 0 of pth of pth shifted
+      (unitvector direction arctime 0 of pth of pth
+        rotated dir scaled scl)..
+          {direction arctime 0 of pth of pth}
+    for i=aux_len step aux_len until pth_len-aux_len:
+      point arctime i of pth of pth shifted
+        (unitvector direction arctime i of pth of pth
+          rotated dir scaled scl)
+            {direction arctime i of pth of pth}..
+    endfor
+    point arctime pth_len of pth of pth shifted
+      (unitvector direction arctime pth_len of pth of pth
+        rotated dir scaled scl)
+          {direction arctime pth_len of pth of pth}
+  else:
+    pth
+  fi
+enddef;
+
+primarydef pth expanded scl_dir_len=
+  expanded_aux (pth,
+    redpart scl_dir_len, greenpart scl_dir_len, bluepart scl_dir_len)
+enddef;
+
+vardef waved_aux (expr pth, amp)=
+  save pth_len, mid;
+  numeric pth_len, mid;
+  pth_len:=arclength pth;
+  if (amp>0) and (pth_len>2(1+sqrt 5)*amp):
+    mid:=pth_len/(2(pth_len div (2(1+sqrt 5)*amp)));
+    point arctime 0 of pth of pth shifted
+      (unitvector direction arctime 0 of pth of pth
+        rotated -90 scaled amp)
+          {direction arctime 0 of pth of pth}
+    for i=mid step 2mid until pth_len:
+    ..point arctime i of pth of pth shifted
+        (unitvector direction arctime i of pth of pth
+          rotated 90 scaled amp)
+            {direction arctime i of pth of pth}
+    ..point arctime i+mid of pth of pth shifted
+        (unitvector direction arctime i+mid of pth of pth
+          rotated -90 scaled amp)
+            {direction arctime i+mid of pth of pth}
+    endfor
+  else:
+    pth
+  fi
+enddef;
+
+primarydef pth waved amp=
+  waved_aux(pth, amp)
+enddef;
+
+vardef drv_styled_aux[] expr pth=
+  save sty_idx, pth_len, pct;
+  numeric sty_idx, pth_len;
+  picture pct;
+  sty_idx:=check_path_style (@, 1);
+  pth_len:=arclength pth;
+  pct:=nullpicture;
+  if sty_idx=1:
+    interim linecap:=butt;
+    addto pct doublepath pth withpen drv_pen;
+  elseif sty_idx=2:
+    interim linecap:=butt;
+    addto pct doublepath pth
+      expanded (1.25rul_thk[drv_sty],  90, rul_thk[drv_sty])
+      withpen drv_pen;
+    addto pct doublepath pth
+      expanded (1.25rul_thk[drv_sty], -90, rul_thk[drv_sty])
+      withpen drv_pen;
+  elseif sty_idx=3:
+    addto pct also pth dotted (rul_thk[drv_sty], 2rul_thk[drv_sty]);
+  elseif sty_idx=4:
+    if rul_thk[drv_sty]>0:
+      interim linecap:=butt;
+      save dsh_num, dsh_len;
+      numeric dsh_num, dsh_len;
+      dsh_num:=round(pth_len/(3rul_thk[drv_sty]));
+      dsh_len:=
+        if odd dsh_num:
+          pth_len/dsh_num
+        else:
+          pth_len/(dsh_num+1)
+        fi;
+      addto pct doublepath pth dashed dashpattern(on dsh_len off dsh_len)
+        withpen drv_pen;
+    fi
+  elseif sty_idx=5:
+    interim linecap:=butt;
+    addto pct doublepath pth
+      waved 1.25rul_thk[drv_sty] withpen drv_pen;
+  elseif (sty_idx=6) and (pth_len>0):
+    addto pct also pth dotted (pdt_hg[drv_sty], pdt_wd[drv_sty]);
+  fi
+  pct
+enddef;
+
+primarydef pth drv_styled sty=
+  drv_styled_aux[sty] pth
+enddef;
+
+
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+%
+% Delimiters
+%
+
+%
+% 1. Global parameters
+%
+
+string drv_l_dlm; % left delimiter LaTeX code
+string drv_r_dlm; % right delimiter LaTeX code
+
+%
+% 2. Macros
+%
+
+vardef minmax_y[]=(
+  if drv_bot_roots:
+    if known ccl[@]:
+      ypart jdg[@].c-num_hg+iln_hg[(iln_sty[ccl[@]])]
+        +min_clr_scl*min_clr[drv_sty]/2
+    else:
+      smin_y[@]-min_clr_scl*min_clr[drv_sty]
+    fi,
+    smax_y[@]+min_clr_scl*min_clr[drv_sty]
+  else:
+    smin_y[@]-min_clr_scl*min_clr[drv_sty],
+    if known ccl[@]:
+      ypart jdg[@].c-den_dp-iln_hg[(iln_sty[ccl[@]])]
+        -min_clr_scl*min_clr[drv_sty]/2
+    else:
+      smax_y[@]+min_clr_scl*min_clr[drv_sty]
+    fi
+  fi)
+enddef;
+
+vardef delim @# expr dlm_len=
+  save rule_str, dlm_str, dlm_pct, dlm_dp;
+  string rule_str, dlm_str;
+  picture dlm_pct;
+  numeric dlm_dp;
+  rule_str:="\rule{0bp}{"&(decimal(dlm_len/2+axis_hg[drv_sty]))&"bp}";
+  dlm_str:=
+    if str @#="l":
+      "\left"&drv_l_dlm&rule_str&"\right."
+    else:
+      "\left."&rule_str&"\right"&drv_r_dlm
+    fi;
+  dlm_pct:=mth_tex[drv_sty] dlm_str;
+  dlm_dp:=depth dlm_pct;
+  if dlm_dp=0:
+    nullpicture
+  else:
+    begingroup
+      setbounds dlm_pct to
+        (xpart llcorner dlm_pct,  dlm_dp)
+      --(xpart ulcorner dlm_pct, -dlm_dp)
+      --(xpart urcorner dlm_pct, -dlm_dp)
+      --(xpart lrcorner dlm_pct,  dlm_dp)
+      --cycle;
+      dlm_pct yscaled (dlm_len/(2*height dlm_pct))
+    endgroup
+  fi
+enddef;
+
+
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+%
+% Checking, building, freezing (very inefficient, to be improved)
+%
+
+%
+% 1. Global parameters
+%
+
+numeric min_clr_scl;		%
+numeric prm_skp_scl;		%
+numeric jdg_skp_scl;		%
+numeric ilb_skp_scl;		%
+numeric plb_skp_scl;		%
+
+boolean drv_bot_roots;		%
+boolean drv_boxmode_on;		%
+boolean drv_fractionmode_on;	%
+string  drv_axis_ref;		%
+
+%
+% 2. Macros
+%
+
+%
+% Checking
+%
+
+vardef fraction_inference[]=
+      (prm_num[@]=0)
+  and (iln_sty[@]=0)
+  and (unknown l_ilb[@])
+  and (unknown r_ilb[@])
+  and drv_fractionmode_on
+enddef;
+
+vardef drv_check_root[]=
+  if unknown jdg[@]:
+    drv_errhelp "An index must be used to declare a both a judgment and an"&
+      " inference.";
+    drv_errmessage (decimal @)&" has been used as an inference index but not"&
+      " as a judgment index";
+  elseif unknown prm_num[@]:
+    drv_errhelp "An index must be used to declare a both a judgment and an"&
+      " inference.";
+    drv_errmessage (decimal @)&" has been used as a judgment index but not"&
+      " as an inference index";
+  else:
+    save i_sty, prm_idx;
+    numeric i_sty, prm_idx;
+    i_sty:=iln_sty[@];
+    for prm_rnk=0 upto prm_num[@]-1:
+      prm_idx:=prm[@][prm_rnk];
+      drv_check_root[prm_idx];
+      %
+      % numerators and denominators clearances
+      % The TEXbook, Appendix G, Rule 15d.
+      %
+      if drv_bot_roots:
+        num_hg:=max(num_hg,
+          iln_hg[i_sty]+min_clr_scl*min_clr[drv_sty]-jdg[prm_idx].dp);
+      else:
+        den_dp:=min(den_dp,
+          iln_dp[i_sty]-min_clr_scl*min_clr[drv_sty]-jdg[prm_idx].hg);
+      fi
+    endfor
+    if not fraction_inference[@]:
+      if drv_bot_roots:
+        den_dp:=min(den_dp,
+          iln_dp[i_sty]-min_clr_scl*min_clr[drv_sty]-jdg[@].hg);
+      else:
+        num_hg:=max(num_hg,
+          iln_hg[i_sty]+min_clr_scl*min_clr[drv_sty]-jdg[@].dp);
+      fi
+    fi
+    if unknown boxed[@]:
+      boxed[@]:=false;
+    fi
+  fi
+enddef;
+
+vardef drv_check=
+  if root_num=0:
+    drv_errhelp "Well ...";
+    drv_errmessage "no inference has been declared";
+  else:
+    save root_idx;
+    numeric root_idx;
+    root_idx:=root[0];
+    drv_check_root[root_idx];
+    if root_num>1:
+      save root_str;
+      string root_str;
+      root_str:=decimal root_idx;
+      for idx=1 upto root_num-1:
+        root_idx:=root[idx];
+        drv_check_root[root_idx];
+        root_str:=root_str&", "&(decimal root_idx);
+      endfor
+      drv_message "warning, multiple root indices ("&root_str&").";
+    fi
+  fi
+  drv_checked:=true;
+enddef;
+
+%
+% Building
+%
+
+vardef drv_build_root[]=
+  %
+  % premises junction (from left to right)
+  %
+  for prm_rnk=0 upto  prm_num[@]-1:
+    drv_build_root[prm[@][prm_rnk]];
+    if prm_rnk>0:
+      save ll_idx, lr_idx, rl_idx, rr_idx;
+      save lmax_x, rmin_x, min_skp;
+      numeric ll_idx, lr_idx, rl_idx, rr_idx;
+      numeric lmax_x, rmin_x, min_skp;
+      ypart jdg[prm[@][prm_rnk-1]].c=ypart jdg[prm[@][prm_rnk]].c;
+      ll_idx:=prm[@][0];
+      lr_idx:=prm[@][prm_rnk-1];
+      rl_idx:=prm[@][prm_rnk];
+      rr_idx:=prm[@][prm_rnk];
+      lmax_x:=imax_x[lr_idx];
+      rmin_x:=imin_x[rl_idx];
+      min_skp[0]:=rmin_x-lmax_x;
+      forever:
+        exitif (unknown r_prm[lr_idx]) or (unknown l_prm[rl_idx]);
+        ll_idx:=l_prm[ll_idx];
+        lr_idx:=r_prm[lr_idx];
+        rl_idx:=l_prm[rl_idx];
+        rr_idx:=r_prm[rr_idx];
+        lmax_x:=max(lmax_x, imax_x[lr_idx]);
+        rmin_x:=min(rmin_x, imin_x[rl_idx]);
+        min_skp[0]:=min(min_skp[0], imin_x[rl_idx]-imax_x[lr_idx]);
+      endfor
+      min_skp[1]:=rmin_x-lmax_x;
+      if known r_prm[lr_idx]:
+        r_prm[rr_idx]:= r_prm[lr_idx];
+        lmax_x:=smax_x[lr_idx];
+      elseif known l_prm[rl_idx]:
+        l_prm[ll_idx]:=l_prm[rl_idx];
+        rmin_x:=smin_x[rl_idx];
+      fi
+      min_skp[2]:=rmin_x-lmax_x;
+      if jct_sty[@]<3:
+        min_skp[jct_sty[@]]=prm_skp_scl*prm_skp[drv_sty];
+      fi
+    fi
+  endfor
+  if  prm_num[@]>0:
+    l_prm[@]:=prm[@][0];
+    r_prm[@]:=prm[@][prm_num[@]-1];
+  fi
+  %
+  % judgment alignment
+  %
+  if prm_num[@]=0:
+    imin_x[@]:=xpart jdg[@].l-jdg_skp_scl*jdg_skp[jdg_sty[drv_sty]];
+    imax_x[@]:=xpart jdg[@].r+jdg_skp_scl*jdg_skp[jdg_sty[drv_sty]];
+  else:
+    save l_xref, r_xref;
+    l_xref=
+      if boxed[prm[@][0]]:
+        smin_x[prm[@][0]]
+      else:
+        xpart jdg[prm[@][0]].l
+      fi;
+    r_xref=
+      if boxed[prm[@][prm_num[@]-1]]:
+        smax_x[prm[@][prm_num[@]-1]]
+      else:
+        xpart jdg[prm[@][prm_num[@]-1]].r
+      fi;
+    if alg_sty[@]="l":
+      xpart jdg[@].l=l_xref;
+    elseif alg_sty[@]="c":
+      xpart jdg[@].c=(l_xref+r_xref)/2;
+    elseif alg_sty[@]="r":
+      xpart jdg[@].r=r_xref;
+    fi
+    imin_x[@]:=min(xpart jdg[@].l, l_xref)
+          -jdg_skp_scl*jdg_skp[jdg_sty[drv_sty]];
+    imax_x[@]:=max(xpart jdg[@].r, r_xref)
+          +jdg_skp_scl*jdg_skp[jdg_sty[drv_sty]];
+  fi
+  %
+  % inference line
+  %
+  save iln_wd, iln_pct;
+  numeric iln_wd;
+  picture iln_pct;
+  iln_wd:=imax_x[@]-imin_x[@];
+  iln_pct:=((0, 0)--(iln_wd, 0)) drv_styled iln_sty[@];
+  setbounds iln_pct to
+    (0, ypart llcorner iln_pct)
+  --(0, ypart ulcorner iln_pct)
+  --(iln_wd, ypart ulcorner iln_pct)
+  --(iln_wd, ypart llcorner iln_pct)
+  --cycle; % ! `linecap:=butt' and `linecap:=squared' -> same bounding box !
+  box_init iln[@] (iln_pct);
+  xpart iln[@].c=(imin_x[@]+imax_x[@])/2;
+  %
+  % orientation, smin_y & smax_y
+  %
+  if drv_bot_roots:
+    ypart iln[@].c=ypart jdg[@].c-den_dp;
+    smin_y[@]:=ypart jdg[@].c+jdg[@].dp;
+    smax_y[@]:=
+      if iln_sty[@]=0:
+        ypart jdg[@].c+jdg[@].hg
+      else:
+        ypart iln[@].c+iln[@].hg
+      fi;
+    if prm_num[@]>0:
+      ypart iln[@].c=ypart jdg[prm[@][0]].c-num_hg;
+      for prm_rnk=0 upto prm_num[@]-1:
+        smax_y[@]:=max(smax_y[@], smax_y[prm[@][prm_rnk]]);
+      endfor;
+    fi
+  else:
+    ypart iln[@].c=ypart jdg[@].c-num_hg;
+    smin_y[@]:=
+      if iln_sty[@]=0:
+        ypart jdg[@].c+jdg[@].dp
+      else:
+        ypart iln[@].c+iln[@].dp
+      fi;
+    smax_y[@]:=ypart jdg[@].c+jdg[@].hg;
+    if prm_num[@]>0:
+      ypart iln[@].c=ypart jdg[prm[@][0]].c-den_dp;
+      for prm_rnk=0 upto prm_num[@]-1:
+        smin_y[@]:=min(smin_y[@], smin_y[prm[@][prm_rnk]]);
+      endfor;
+    fi
+  fi
+  %
+  % inference labels
+  %
+  if known l_ilb[@]:
+    l_ilb[@].r=iln[@].l shifted (-ilb_skp_scl*ilb_skp[drv_sty], 0);
+    imin_x[@]:=xpart l_ilb[@].l;
+    smin_y[@]:=min(smin_y[@], ypart l_ilb[@].c+l_ilb[@].dp);
+    smax_y[@]:=max(smax_y[@], ypart l_ilb[@].c+l_ilb[@].hg);
+  fi
+  if known r_ilb[@]:
+    r_ilb[@].l=iln[@].r shifted (ilb_skp_scl*ilb_skp[drv_sty], 0);
+    imax_x[@]:=xpart r_ilb[@].r;
+    smin_y[@]:=min(smin_y[@], ypart r_ilb[@].c+r_ilb[@].dp);
+    smax_y[@]:=max(smax_y[@], ypart r_ilb[@].c+r_ilb[@].hg);
+  fi
+  %
+  % phantom steps
+  %
+  if known tgt[@]:
+    save phm_pth, phm_pct;
+    path phm_pth;
+    picture phm_pct;
+    save top_y, mid_y, bot_y;
+    numeric top_y, bot_y;
+    if drv_bot_roots:
+      bot_y:=xpart minmax_y[@]+min_clr_scl*min_clr[drv_sty]/2;
+      top_y:=xpart minmax_y[tgt[@]];
+    else:
+      bot_y:=ypart minmax_y[tgt[@]];
+      top_y:=ypart minmax_y[@]-min_clr_scl*min_clr[drv_sty]/2;
+    fi
+    mid_y:=(top_y+bot_y)/2;
+    phm_pth:=(0, (bot_y-top_y)/2)--(0, (top_y-bot_y)/2);
+    phm_pct:=phm_pth drv_styled phm_sty[@];
+    box_init phm[@] (phm_pct shifted ((width phm_pct)/2, 0));
+    phm[@].c=(xpart jdg[@].c, mid_y);
+    imin_x[@]:=min(imin_x[@], xpart phm[@].l);
+    imax_x[@]:=max(imax_x[@], xpart phm[@].r);
+    %
+    % phantom steps labels
+    %
+    if known l_plb[@]:
+      l_plb[@].r=phm[@].l shifted (-plb_skp[drv_sty], 0);
+      imin_x[@]:=min(imin_x[@], xpart l_plb[@].l);
+    fi
+    if known r_plb[@]:
+      r_plb[@].l=phm[@].r shifted ( plb_skp[drv_sty], 0);
+      imax_x[@]:=max(imax_x[@], xpart r_plb[@].r);
+    fi
+  fi
+  %
+  % smin_x & smax_x
+  %
+  smin_x[@]:=imin_x[@];
+  smax_x[@]:=imax_x[@];
+  for prm_rnk=0 upto prm_num[@]-1:
+    smin_x[@]:=min(smin_x[@], smin_x[prm[@][prm_rnk]]);
+    smax_x[@]:=max(smax_x[@], smax_x[prm[@][prm_rnk]]);
+  endfor
+  %
+  % delimiters
+  %
+  if known l_dlb[@] or known r_dlb[@]:
+    save idx, mmy, min_y, max_y;
+    numeric idx, min_y, max_y;
+    pair mmy;
+    mmy:=minmax_y[@];
+    min_y:=xpart mmy;
+    max_y:=ypart mmy;
+    if known l_dlb[@]:
+      box_init l_dlm[@] (delim l (max_y-min_y));
+      l_dlm[@].r=(smin_x[@], (max_y+min_y)/2);
+      l_dlb[@].r=l_dlm[@].l;
+      smin_x[@]:=xpart l_dlb[@].l;
+    fi
+    if known r_dlb[@]:
+      box_init r_dlm[@] (delim r (max_y-min_y));
+      r_dlm[@].l=(smax_x[@], (max_y+min_y)/2);
+      r_dlb[@].l=r_dlm[@].r;
+      smax_x[@]:=xpart r_dlb[@].r;
+    fi
+  fi
+  if (known l_dlb[@]) or boxed[@]:
+    idx:=@;
+    forever:
+      imin_x[idx]:=smin_x[@];
+      exitif unknown l_prm[idx];
+      idx:=l_prm[idx];
+    endfor
+  fi
+  if (known r_dlb[@]) or boxed[@]:
+    idx:=@;
+    forever:
+      imax_x[idx]:=smax_x[@];
+      exitif unknown r_prm[idx];
+      idx:=r_prm[idx];
+    endfor
+  fi
+enddef;
+
+vardef drv_build=
+  if not drv_checked:
+    drv_check;
+  fi
+  for idx=0 upto root_num-1:
+    drv_build_root[root[idx]];
+  endfor
+  drv_built:=true;
+enddef;
+
+%
+% Freezing
+%
+
+vardef drv_freeze_root[]=
+  for prm_rnk=0 upto prm_num[@]-1:
+    drv_freeze_root[prm[@][prm_rnk]];
+  endfor
+  for sbj_rnk=0 upto sbj_num[@]-1:
+    box_freeze sbj[@][sbj_rnk];
+  endfor
+  forsuffixes sfx=
+    iln, jdg, phm,
+    l_dlb, l_dlm, l_ilb, l_plb,
+    r_dlb, r_dlm, r_ilb, r_plb:
+      if known sfx[@]:
+        box_freeze sfx[@];
+      fi
+  endfor
+enddef;
+
+vardef drv_freeze=
+  if not drv_built:
+    drv_build;
+  fi
+  save root_idx;
+  numeric root_idx;
+  root_idx:=root[0];
+  if unknown iln[root_idx].c:
+    %
+    % default math axis
+    %
+    if drv_axis_ref="iln":
+      iln[root_idx].c=(0, axis_hg[drv_sty]);
+    else: % drv_axis_ref="jdg"
+      jdg[root_idx].c=(0, axis_hg[drv_sty]);
+    fi
+    drv_freeze_root[root_idx];
+  fi
+  for idx=1 upto root_num-1:
+    root_idx:=root[idx];
+    if unknown iln[root_idx].c:
+      smin_x[root_idx]=smax_x[root[idx-1]]+prm_skp_scl*prm_skp[drv_sty];
+      ypart iln[root_idx].c=ypart iln[root[idx-1]].c;
+    fi
+    drv_freeze_root[root_idx];
+  endfor
+  drv_frozen:=true;
+enddef;
+
+
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+%
+% Derivation tree pictures
+%
+
+%
+% 1. Global parameters
+%
+
+boolean drv_proofmode_on;	%
+color prf_clr;			%
+color jdg_clr;			%
+color sbj_clr;			%
+
+prf_clr:=.75background;		% arbitrary
+jdg_clr:=red;			% arbitrary
+sbj_clr:=blue;			% arbitrary
+
+%
+% 2. Macros
+%
+
+vardef drv_tree_addto @# (expr idx) text draw_options=
+  for prm_rnk=0 upto prm_num[idx]-1:
+    drv_tree_addto @# (prm[idx][prm_rnk]) draw_options;
+  endfor
+  forsuffixes sfx=
+    jdg, phm,
+    l_dlb, l_dlm, l_ilb, l_plb,
+    r_dlb, r_dlm, r_ilb, r_plb:
+      if known sfx[idx]:
+        addto @# also sfx[idx] draw_options;
+      fi
+  endfor
+  if iln_sty[idx]>0:
+      addto @# also iln[idx] draw_options;
+  fi
+enddef;
+
+vardef tt_nat[] expr nat= % typewriter typeface naturals
+  save nat_aux, nat_pct_wd, dgt_num, nat_pct;
+  numeric nat_aux, nat_pct_wd, dgt_num;
+  picture nat_pct;
+  nat_aux:=abs nat;
+  nat_pct:=nullpicture;
+  nat_pct_wd:=0;
+  dgt_num:=1;
+  forever:
+    exitif nat_aux div (10**dgt_num)=0;
+    dgt_num:=dgt_num+1;
+  endfor
+  for rnk:=1 upto dgt_num:
+    addto nat_pct also tt_dgt[@][nat_aux div (10**(dgt_num-rnk))]
+      shifted (nat_pct_wd, 0);
+    nat_pct_wd:=width nat_pct;
+    nat_aux:=nat_aux mod (10**(dgt_num-rnk));
+  endfor
+  nat_pct shifted (0, -axis_hg[@])
+enddef;
+
+vardef prf_tree_addto @# expr idx=
+  for prm_rnk=0 upto prm_num[idx]-1:
+    prf_tree_addto @# (prm[idx][prm_rnk]);
+  endfor
+  if idx>=0:
+    box_init jdg_prf[idx] (tt_nat[2] idx);
+    jdg_prf[idx].r=jdg[idx].l;
+    box_freeze jdg_prf[idx];
+    addto @# also jdg_prf[idx] withcolor jdg_clr;
+    addto @# doublepath jdg[idx].c withcolor jdg_clr
+      withpen pencircle scaled (2*pdt_hg[drv_sty]);
+  fi
+  for sbj_rnk=0 upto sbj_num[idx]-1:
+    box_init sbj_prf[idx][sbj_rnk] (tt_nat[3] sbj_rnk);
+    if odd sbj_rnk:
+      sbj_prf[idx][sbj_rnk].c shifted (0, sbj_prf[idx][sbj_rnk].hg)=
+        sbj[idx][sbj_rnk].c
+          shifted (0, -den_dp-min_clr_scl*min_clr[drv_sty]/2);
+    else:
+      sbj_prf[idx][sbj_rnk].c shifted (0, sbj_prf[idx][sbj_rnk].dp)=
+        sbj[idx][sbj_rnk].c
+          shifted (0, -num_hg+min_clr_scl*min_clr[drv_sty]/2);
+    fi
+    box_freeze sbj_prf[idx][sbj_rnk];
+    addto @# also sbj_prf[idx][sbj_rnk] withcolor sbj_clr;
+    addto @# doublepath sbj[idx][sbj_rnk].c withcolor sbj_clr
+      withpen pencircle scaled pdt_hg[drv_sty];
+  endfor
+enddef;
+
+vardef drv_tree=
+  save pct;
+  picture pct;
+  pct:=nullpicture;
+  if not drv_frozen:
+    drv_freeze;
+  fi
+  for root_idx=0 upto root_num-1:
+    if drv_proofmode_on:
+      drv_tree_addto pct (root[root_idx]) withcolor prf_clr;
+      prf_tree_addto pct (root[root_idx]);
+    else:
+      drv_tree_addto pct (root[root_idx]);
+    fi
+  endfor
+  pct
+enddef;
+
+vardef drv_bbox[]=
+  save min_x, max_x, mmy, min_y, max_y;
+  pair mmy;
+  numeric min_x, max_x, max_y, min_y;
+  if not drv_frozen:
+    drv_freeze;
+  fi
+  min_x:=
+    if known l_dlm[@].r:
+      xpart l_dlm[@].r
+    else:
+      smin_x[@]
+    fi-jdg_skp_scl*jdg_skp[jdg_sty[drv_sty]];
+  max_x:=
+    if known r_dlm[@].l:
+      xpart l_dlm[@].l
+    else:
+      smax_x[@]
+    fi+jdg_skp_scl*jdg_skp[jdg_sty[drv_sty]];
+  mmy:=minmax_y[@];
+  min_y:=xpart mmy;
+  max_y:=ypart mmy;
+  (min_x, min_y)--
+  (min_x, max_y)--
+  (max_x, max_y)--
+  (max_x, min_y)--
+  cycle
+enddef;
+
+vardef mth_axis @# (suffix ref_sfx) (expr idx)=
+  if not drv_frozen:
+    drv_freeze;
+  fi
+  if unknown prm_num[idx]:
+    drv_errhelp "An index must be used to declare an inference before it is"&
+      " used to set the math axis of a picture.";
+    drv_errmessage "no inference has been declared using index "&(decimal idx);
+  else:
+    save ref_str, yref;
+    string ref_str;
+    numeric yref;
+    ref_str:=str ref_sfx;
+    if ref_str="iln":
+      yref:=ypart iln[idx].c;
+    elseif ref_str="jdg":
+      yref:=ypart jdg[idx].c;
+    elseif ref_str="dlm":
+      if known l_dlm[idx]:
+        yref:=ypart l_dlm[idx].c;
+      elseif known r_dlm[idx]:
+        yref:=ypart r_dlm[idx].c;
+      else:
+        drv_errhelp "Well ...";
+        drv_errmessage "no delimiter is attached to inference "&(decimal idx);
+      fi
+    else:
+      drv_errhelp "Valid identifiers are"&
+        " iln (inference line axis),"&
+        " jdg (judgment math-axis) and"&
+        " dlm (delimiter axis).";
+      drv_errmessage (ref_str&" is not a valid reference type identifier");
+    fi
+    if known yref:
+      @#:=@# shifted (0, axis_hg[drv_sty]-yref);
+    fi
+  fi
+enddef;
+
+vardef drv_axis (suffix ref) (expr idx)=
+  mth_axis currentpicture (ref, idx);
+enddef;
+
+
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+%
+% Tunings
+%
+
+vardef check_math_style (expr sty_str, default)=
+  if sty_str="\displaystyle":
+    0
+  elseif sty_str="\textstyle":
+    1
+  elseif sty_str="\scriptstyle":
+    2
+  elseif sty_str="\scriptscriptstyle":
+    3
+  else:
+    begingroup
+      drv_errhelp "Valid commands are"&
+        " \displaystyle,"&
+        " \textstyle,"&
+        " \scriptstyle and"&
+        " \scriptscriptstyle.";
+      drv_errmessage (sty_str&" is not a valid math-style command");
+      default
+    endgroup
+  fi
+enddef;
+
+vardef check_position_left (suffix pos_sfx) (expr default)=
+  save pos_str;
+  string pos_str;
+  pos_str:=str pos_sfx;
+  if (pos_str="l"):
+    true
+  elseif (pos_str="r"):
+    false
+  else:
+    begingroup
+      drv_errhelp "Valid identifiers are l (left) and r (right).";
+      drv_errmessage (pos_str&" is not a valid label position identifier");
+      default
+    endgroup
+  fi
+enddef;
+
+vardef check_mode_on (suffix status_sfx) (expr default)=
+  save status_str;
+  string status_str;
+  status_str:=str status_sfx;
+  if status_str="on":
+    true
+  elseif status_str="off":
+    false
+  else:
+    begingroup
+      drv_errhelp "Possible identifiers are on and off";
+      drv_errmessage (status_str&" is not a valid status identifier");
+      default
+    endgroup
+  fi
+enddef;
+
+vardef drv_math_style (suffix typ_sfx) (expr sty_str)=
+  save typ_str, sty_idx;
+  string typ_str;
+  numeric sty_idx;
+  typ_str:=str typ_sfx;
+  if  (typ_str<>"drv")
+  and (typ_str<>"jdg")
+  and (typ_str<>"ilb")
+  and (typ_str<>"dlb")
+  and (typ_str<>"plb"):
+    drv_errhelp "Valid  identifiers are"&
+      " drv (derivation tree),"&
+      " jdg (judgment),"&
+      " ilb (inference label),"&
+      " dlb (delimiter label) and"&
+      " plb (phantom steps label).";
+    drv_errmessage (sty_str&" is not a valid component identifier");
+  else:
+    sty_idx:=check_math_style (sty_str, 0);
+    if typ_str="drv":
+      drv_sty:=sty_idx;
+    else:
+      forsuffixes sfx=scantokens (typ_str&"_sty"):
+        for idx=0 upto 3:
+          sfx[idx]:=min(idx+sty_idx, 3);
+        endfor
+      endfor
+    fi
+  fi
+enddef;
+
+vardef drv_scale (suffix scl_sfx) (expr scl)=
+  save scl_str;
+  string scl_str;
+  scl_str:=str scl_sfx;
+  if scl_str="clr":
+    min_clr_scl:=scl;
+  elseif scl_str="prm":
+    prm_skp_scl:=scl;
+  elseif (scl_str="jdg") or (scl_str="jgm"): % "jgm" is deprecated
+    jdg_skp_scl:=scl;
+  elseif (scl_str="ilb") or (scl_str="lbl"): % "lbl" is deprecated
+    ilb_skp_scl:=scl;
+  else:
+    drv_errhelp "Valid identifiers are"&
+      " clr,"&
+      " prm,"&
+      " jdg and"&
+      " ilb.";
+    drv_errmessage (scl_str&" is not a valid scale identifier");
+  fi
+enddef;
+
+vardef drv_junction_style suffix sty_sfx=
+  drv_jct_sty:=check_junction_style (sty_sfx, drv_jct_sty);
+enddef;
+
+vardef drv_alignment_style suffix sty_sfx=
+  drv_alg_sty:=check_alignment_style (sty_sfx, drv_alg_sty);
+enddef;
+
+vardef drv_path_style (suffix typ_sfx, sty_sfx)=
+  save typ_str;
+  string typ_str;
+  typ_str:=str typ_sfx;
+  if typ_str="iln":
+    drv_iln_sty:=check_path_style (sty_sfx, drv_iln_sty);
+  elseif typ_str="phm":
+    drv_phm_sty:=check_path_style (sty_sfx, drv_phm_sty);
+  else:
+    drv_errhelp "Valid identifiers are"&
+      " iln (inference line) and"&
+      " phm (phantom steps path).";
+    drv_errmessage (typ_str&" is not a valid path-type identifier");
+  fi
+enddef;
+
+vardef drv_labels_position_aux (suffix typ_sfx, pos_sfx)=
+  save typ_str, idt_str, pos_str;
+  string typ_str, idt_str, pos_str;
+  typ_str:=str typ_sfx;
+  if  typ_str="ilb":
+    drv_left_ilb:=check_position_left (pos_sfx, drv_left_ilb);
+  elseif typ_str="dlb":
+    drv_left_dlb:=check_position_left (pos_sfx, drv_left_dlb);
+  elseif typ_str="plb":
+    drv_left_plb:=check_position_left (pos_sfx, drv_left_plb);
+  else:
+    drv_errhelp "Valid identifiers are"&
+      " ilb (inference label),"&
+      " dlb (delimiter label) and"&
+      " plb (phantom steps label).";
+    drv_errmessage (typ_str&" is not a valid label-type identifier");
+  fi
+enddef;
+
+vardef drv_labels_position text ARG=
+  drv_labels_position_aux if pair ARG: ARG else: (ilb, ARG) fi;
+enddef;
+
+vardef drv_roots_position suffix pos_sfx=
+  save pos_str;
+  string pos_str;
+  pos_str:=str pos_sfx;
+  if pos_str="t":
+    drv_bot_roots:=false;
+  elseif pos_str="b":
+    drv_bot_roots:=true;
+  else:
+    drv_errhelp "Valid identifiers are"&
+      " t (top) and"&
+      " b (bottom).";
+    drv_errmessage (pos_str&" is not a valid root position identifier");
+  fi
+enddef;
+
+vardef drv_axis_reference suffix ref_sfx=
+  save ref_str;
+  string ref_str;
+  ref_str:=str ref_sfx;
+  if (ref_str<>"iln") and (ref_str<>"jdg"):
+    drv_errhelp "Valid identifiers are iln (inference line axis) and"&
+      " jdg (judgment math-axis).";
+    drv_errmessage (ref_str&" is not a valid reference identifier");
+  else:
+    drv_axis_ref:=ref_str;
+  fi
+enddef;
+
+vardef drv_delimiter (suffix pos_sfx) (expr dlm_str)=
+  if check_position_left (pos_sfx, true):
+    drv_l_dlm:=dlm_str;
+  else:
+    drv_r_dlm:=dlm_str;
+  fi
+enddef;
+
+vardef drv_left_delimiter expr dlm_str=
+  drv_delimiter (l, dlm_str);
+enddef;
+
+vardef drv_right_delimiter expr dlm_str=
+  drv_delimiter (r, dlm_str);
+enddef;
+
+vardef drv_box_mode suffix status_sfx=
+  drv_boxmode_on:=check_mode_on (status_sfx, drv_boxmode_on);
+enddef;
+
+vardef drv_fraction_mode suffix status_sfx=
+  drv_fractionmode_on:=check_mode_on (status_sfx, drv_fractionmode_on);
+enddef;
+
+vardef drv_proof_mode suffix status_sfx=
+  drv_proofmode_on:=check_mode_on (status_sfx, drv_proofmode_on);
+enddef;
+
+
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+%
+% Default settings
+%
+
+drv_font_size "\normalsize";
+drv_math_style (drv, "\displaystyle");
+drv_math_style (jdg, "\textstyle");
+drv_math_style (ilb, "\scriptstyle");
+drv_math_style (dlb, "\textstyle");
+drv_math_style (plb, "\textstyle");
+drv_scale (clr, 1);
+drv_scale (prm, 1);
+drv_scale (jdg, 1);
+drv_scale (ilb, 1);
+drv_junction_style 1;
+drv_alignment_style c;
+drv_path_style (iln, 1);
+drv_path_style (phm, 3);
+drv_labels_position (ilb, r);
+drv_labels_position (dlb, l);
+drv_labels_position (plb, l);
+drv_roots_position b;
+drv_axis_reference iln;
+drv_left_delimiter "\lbrace";
+drv_right_delimiter "\rbrace";
+drv_box_mode off;
+drv_fraction_mode on;
+drv_proof_mode off;
+
+
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+%
+% LaTeX inclusion macro
+%
+% \drv includes a picture file in such a way that the baseline of the included
+% picture coincides with the baseline of the inclusion point. The code for \drv
+% was suggested by Josselin Noirel on the fr.comp.text.tex usenet group.
+%
+% \usepackage{graphicx}
+% \makeatletter
+% \def\Gin@def@bp#1\relax#2#3{\gdef#2{#3}}
+% \newsavebox{\graphicsbox}
+% \newcommand*{\drv}[1]{%
+% \sbox{\graphicsbox}{\includegraphics{#1}}%
+% \raisebox{\Gin@lly bp}%
+% {\usebox{\graphicsbox}}}
+% \makeatother
diff --git a/Master/texmf-dist/doc/metapost/drv/doc/makefile b/Master/texmf-dist/doc/metapost/drv/doc/makefile
new file mode 100644
index 00000000000..ce2f2b8c6cf
--- /dev/null
+++ b/Master/texmf-dist/doc/metapost/drv/doc/makefile
@@ -0,0 +1,46 @@
+MAIN=			drv-guide
+
+$(MAIN).pdf:		$(MAIN).ps
+			ps2pdf $(MAIN).ps
+
+$(MAIN).ps:		$(MAIN).tex $(MAIN)-delayed.mp
+			latex $(MAIN)
+			latex $(MAIN)
+			latex $(MAIN)
+			dvips $(MAIN) -o
+
+$(MAIN)-proof.pdf:	$(MAIN)-proof.ps
+			ps2pdf $(MAIN)-proof.ps
+
+$(MAIN)-proof.ps:	$(MAIN)-delayed.mp
+			latex $(MAIN)-proof
+			dvips $(MAIN)-proof -o
+
+$(MAIN)-delayed.mp:	$(MAIN).mp
+			$(RM) $(MAIN)-delayed.mp
+			mpost $(MAIN)
+			mpost $(MAIN)
+			mpost $(MAIN)
+
+.SILENT clean:
+			$(RM) drv.mpx
+			$(RM) $(MAIN).[0-9]*
+			$(RM) $(MAIN).aux
+			$(RM) $(MAIN).dvi
+			$(RM) $(MAIN).log
+			$(RM) $(MAIN).nav
+			$(RM) $(MAIN).out
+			$(RM) $(MAIN).toc
+			$(RM) $(MAIN)-delayed.mp
+			$(RM) $(MAIN)-delayed.mpx
+			$(RM) $(MAIN)-proof.aux
+			$(RM) $(MAIN)-proof.dvi
+			$(RM) $(MAIN)-proof.log
+			$(RM) $(MAIN)-proof.tex
+			$(RM) $(MAIN)-proof.toc
+
+cleanall:		clean
+			$(RM) $(MAIN).pdf
+			$(RM) $(MAIN).ps
+			$(RM) $(MAIN)-proof.pdf
+			$(RM) $(MAIN)-proof.ps
diff --git a/Master/texmf-dist/doc/metapost/drv/doc/readme.txt b/Master/texmf-dist/doc/metapost/drv/doc/readme.txt
new file mode 100644
index 00000000000..66f2719391a
--- /dev/null
+++ b/Master/texmf-dist/doc/metapost/drv/doc/readme.txt
@@ -0,0 +1,17 @@
+# In order to compile the sources and to get a pdf file, use `make' or:
+
+# 1. run metapost THREE TIMES:
+mpost drv-guide.mp
+mpost drv-guide.mp
+mpost drv-guide.mp
+
+# 2. run latex (three times):
+latex drv-guide.tex
+latex drv-guide.tex
+latex drv-guide.tex
+
+# 3. run dvips (once):
+dvips drv-guide.dvi -o
+
+# 4. run ps2pdf (once):
+ps2pdf drv-guide.ps
diff --git a/Master/texmf-dist/doc/metapost/drv/drv-guide.pdf b/Master/texmf-dist/doc/metapost/drv/drv-guide.pdf
new file mode 100644
index 00000000000..ab7d917ba9e
--- /dev/null
+++ b/Master/texmf-dist/doc/metapost/drv/drv-guide.pdf
diff --git a/Master/texmf-dist/doc/metapost/drv/sample/coq-sample.mp b/Master/texmf-dist/doc/metapost/drv/sample/coq-sample.mp
new file mode 100644
index 00000000000..c10dc3972c4
--- /dev/null
+++ b/Master/texmf-dist/doc/metapost/drv/sample/coq-sample.mp
@@ -0,0 +1,101 @@
+input drv;
+
+verbatimtex %&latex
+
+% Any piece of code related to font selection in the preambule of
+% `coq-sample.tex' (document class, font package, font selection commands ...)
+% should be reported here.
+
+\documentclass[8pt]{beamer}
+\usepackage[T1]{fontenc}
+\usepackage{amsmath}
+\usepackage[varg]{txfonts}
+\newcommand{\var}{\text{Var}}
+\newcommand{\app}{\text{App}}
+\newcommand{\lam}{\text{Lam}}
+\begin{document}
+etex;
+
+drv_font_size "\small";
+drv_labels_position l;
+
+for index=0 upto 6:
+  beginfig(index)
+  jgm 0	"\vdash", "(P\to(Q\to R))\to(Q\to(P\to R))";
+    jgm 1 "P\to(Q\to R)\vdash", "Q\to(P\to R)";
+      jgm 2 "P\to(Q\to R), Q\vdash", "P\to R";
+        jgm 3 "P\to(Q\to R), Q, P\vdash", "R";
+          jgm 4 "P\to(Q\to R), Q, P\vdash", "Q\to R";
+            jgm 5 "P\to(Q\to R), Q, P\vdash", "P\to(Q\to R)";
+            jgm 6 "P\to(Q\to R), Q, P\vdash", "P";
+          jgm 7 "P\to(Q\to R), Q, P\vdash", "Q";
+  nfr 0 (1) ("\lam", 1);
+    nfr 1 (2) ("\lam", 1);
+      nfr 2 (3) ("\lam", 1);
+        nfr 3 (4, 7) ("\app", 1);
+          nfr 4 (5, 6) ("\app", 1);
+            nfr 5 () ("\var", 1);
+            nfr 6 () ("\var", 1);
+          nfr 7 () ("\var", 1);
+  setbounds currentpicture to drv_bbox 0;
+    % All the pictures will have the same bounding box
+    % as the complete derivation tree.
+  draw sbj[0][0];
+  if index=0:
+    draw sbj[0][1] withcolor blue;
+  else:
+    draw sbj[0][1];
+    draw iln[0];
+    draw l_ilb[0];
+    draw sbj[1][0];
+    if index=1:
+      draw sbj[1][1] withcolor blue;
+    else:
+      draw sbj[1][1];
+      draw iln[1];
+      draw l_ilb[1];
+      draw sbj[2][0];
+      if index=2:
+        draw sbj[2][1] withcolor blue;
+      else:
+        draw sbj[2][1];
+        draw iln[2];
+        draw l_ilb[2];
+        draw sbj[3][0];
+        if index=3:
+          draw sbj[3][1] withcolor blue;
+        else:
+          draw sbj[3][1];
+          draw iln[3];
+          draw l_ilb[3];
+          draw jdg[4];
+          draw iln[4];
+          draw l_ilb[4];
+            draw jdg[5];
+            draw iln[5];
+            draw l_ilb[5];
+            draw sbj[6][0];
+          draw sbj[7][0];
+          if index=4:
+            draw sbj[6][1] withcolor blue;
+            draw sbj[7][1] withcolor blue;
+          else:
+            draw sbj[6][1];
+            draw iln[6];
+            draw l_ilb[6];
+            if index=5:
+              draw sbj[7][1] withcolor blue;
+            else:
+              draw sbj[7][1];
+              draw iln[7];
+              draw l_ilb[7];
+            fi
+          fi
+        fi
+      fi
+    fi
+  fi
+  endfig;
+endfor
+
+end
diff --git a/Master/texmf-dist/doc/metapost/drv/sample/coq-sample.tex b/Master/texmf-dist/doc/metapost/drv/sample/coq-sample.tex
new file mode 100644
index 00000000000..d572ef3e7b0
--- /dev/null
+++ b/Master/texmf-dist/doc/metapost/drv/sample/coq-sample.tex
@@ -0,0 +1,258 @@
+% Any piece of code related to font selection in the following preambule
+% (document class, font package, font selection commands ...) should be
+% reported in `coq-sample.mp'.
+
+\documentclass[8pt]{beamer}
+\usetheme{Warsaw}
+
+\usepackage[T1]{fontenc}
+\usepackage{amsmath}
+\usepackage[varg]{txfonts}
+
+\usepackage{graphicx}
+\makeatletter
+\def\Gin@def@bp#1\relax#2#3{\gdef#2{#3}}
+\newsavebox{\graphicsbox}
+\newcommand*{\drv}[1]{%
+\sbox{\graphicsbox}{\includegraphics{#1}}%
+\raisebox{\Gin@lly bp}%
+{\usebox{\graphicsbox}}}
+\makeatother
+
+\title{Une construction de preuve en logique minimale}
+\institute{INF462 -- Master S\&T Informatique -- Bordeaux 1}
+\date{}
+
+\begin{document}
+
+\begin{frame}
+\titlepage
+\end{frame}
+
+\ttfamily
+\itshape
+\small
+
+\begin{frame}
+\begin{block}{}
+%
+% coq-tex output
+%
+\begin{overlayarea}{\textwidth}{.5\textheight}
+\only<1>{%
+  \textup{Coq~{<}~Variables~P~Q~R~:~Prop.}\\
+  P~is~assumed\\
+  Q~is~assumed\\
+  R~is~assumed\\
+  \medskip
+  \textup{%
+  Coq~{<}~Lemma~imp\_perm~:~(P~-{>}~(Q~-{>}~R))~-{>}~(Q~-{>}~(P~-{>}~R)).}\\
+  1~subgoal\\
+  ~~\\
+  ~~P~:~Prop\\
+  ~~Q~:~Prop\\
+  ~~R~:~Prop\\
+  ~~============================\\
+  ~~~\textcolor{blue}{(P~-{>}~Q~-{>}~R)~-{>}~Q~-{>}~P~-{>}~R}\\
+  \medskip
+  \textup{Coq~{<}~Proof.}\\
+  \medskip
+  \textup{Coq~{<}}}
+\only<2>{%
+  \textup{Coq~{<}~Variables~P~Q~R~:~Prop.}\\
+  P~is~assumed\\
+  Q~is~assumed\\
+  R~is~assumed\\
+  \medskip
+  \textup{%
+  Coq~{<}~Lemma~imp\_perm~:~(P~-{>}~(Q~-{>}~R))~-{>}~(Q~-{>}~(P~-{>}~R)).}\\
+  1~subgoal\\
+  ~~\\
+  ~~P~:~Prop\\
+  ~~Q~:~Prop\\
+  ~~R~:~Prop\\
+  ~~============================\\
+  ~~~\textcolor{blue}{(P~-{>}~Q~-{>}~R)~-{>}~Q~-{>}~P~-{>}~R}\\
+  \medskip
+  \textup{Coq~{<}~Proof.}\\
+  \medskip
+  \textup{Coq~{<}~~~intro~H.}}
+\only<3>{%
+  \textup{Coq~{<}~~~intro~H.}\\
+  1~subgoal\\
+  ~~\\
+  ~~P~:~Prop\\
+  ~~Q~:~Prop\\
+  ~~R~:~Prop\\
+  ~~H~:~P~-{>}~Q~-{>}~R\\
+  ~~============================\\
+  ~~~\textcolor{blue}{Q~-{>}~P~-{>}~R}\\
+  \medskip
+  \textup{Coq~{<}}}
+\only<4>{%
+  \textup{Coq~{<}~~~intro~H.}\\
+  1~subgoal\\
+  ~~\\
+  ~~P~:~Prop\\
+  ~~Q~:~Prop\\
+  ~~R~:~Prop\\
+  ~~H~:~P~-{>}~Q~-{>}~R\\
+  ~~============================\\
+  ~~~\textcolor{blue}{Q~-{>}~P~-{>}~R}\\
+  \medskip
+  \textup{Coq~{<}~~~intro~q.}}
+\only<5>{%
+  \textup{Coq~{<}~~~intro~q.}\\
+  1~subgoal\\
+  ~~\\
+  ~~P~:~Prop\\
+  ~~Q~:~Prop\\
+  ~~R~:~Prop\\
+  ~~H~:~P~-{>}~Q~-{>}~R\\
+  ~~q~:~Q\\
+  ~~============================\\
+  ~~~\textcolor{blue}{P~-{>}~R}\\
+  \medskip
+  \textup{Coq~{<}}}
+\only<6>{%
+  \textup{Coq~{<}~~~intro~q.}\\
+  1~subgoal\\
+  ~~\\
+  ~~P~:~Prop\\
+  ~~Q~:~Prop\\
+  ~~R~:~Prop\\
+  ~~H~:~P~-{>}~Q~-{>}~R\\
+  ~~q~:~Q\\
+  ~~============================\\
+  ~~~\textcolor{blue}{P~-{>}~R}\\
+  \medskip
+  \textup{Coq~{<}~~~intro~p.}}
+\only<7>{%
+  \textup{Coq~{<}~~~intro~p.}\\
+  1~subgoal\\
+  ~~\\
+  ~~P~:~Prop\\
+  ~~Q~:~Prop\\
+  ~~R~:~Prop\\
+  ~~H~:~P~-{>}~Q~-{>}~R\\
+  ~~q~:~Q\\
+  ~~p~:~P\\
+  ~~============================\\
+  ~~~\textcolor{blue}{R}\\
+  \medskip
+  \textup{Coq~{<}}}
+\only<8>{%
+  \textup{Coq~{<}~~~intro~p.}\\
+  1~subgoal\\
+  ~~\\
+  ~~P~:~Prop\\
+  ~~Q~:~Prop\\
+  ~~R~:~Prop\\
+  ~~H~:~P~-{>}~Q~-{>}~R\\
+  ~~q~:~Q\\
+  ~~p~:~P\\
+  ~~============================\\
+  ~~~\textcolor{blue}{R}\\
+  \medskip
+  \textup{Coq~{<}~~~apply~H.}}
+\only<9>{%
+  \textup{Coq~{<}~~~apply~H.}\\
+  2~subgoals\\
+  ~~\\
+  ~~P~:~Prop\\
+  ~~Q~:~Prop\\
+  ~~R~:~Prop\\
+  ~~H~:~P~-{>}~Q~-{>}~R\\
+  ~~q~:~Q\\
+  ~~p~:~P\\
+  ~~============================\\
+  ~~~\textcolor{blue}{P}\\
+  subgoal~2~is:\\
+  ~\textcolor{blue}{Q}\\
+  \medskip
+  \textup{Coq~{<}}}
+\only<10>{%
+  \textup{Coq~{<}~~~apply~H.}\\
+  2~subgoals\\
+  ~~\\
+  ~~P~:~Prop\\
+  ~~Q~:~Prop\\
+  ~~R~:~Prop\\
+  ~~H~:~P~-{>}~Q~-{>}~R\\
+  ~~q~:~Q\\
+  ~~p~:~P\\
+  ~~============================\\
+  ~~~\textcolor{blue}{P}\\
+  subgoal~2~is:\\
+  ~\textcolor{blue}{Q}\\
+  \medskip
+  \textup{Coq~{<}~~~assumption.}}
+\only<11>{%
+  \textup{Coq~{<}~~~assumption.}\\
+  1~subgoal\\
+  ~~\\
+  ~~P~:~Prop\\
+  ~~Q~:~Prop\\
+  ~~R~:~Prop\\
+  ~~H~:~P~-{>}~Q~-{>}~R\\
+  ~~q~:~Q\\
+  ~~p~:~P\\
+  ~~============================\\
+  ~~~\textcolor{blue}{Q}\\
+  \medskip
+  \textup{Coq~{<}}}
+\only<12>{%
+  \textup{Coq~{<}~~~assumption.}\\
+  1~subgoal\\
+  ~~\\
+  ~~P~:~Prop\\
+  ~~Q~:~Prop\\
+  ~~R~:~Prop\\
+  ~~H~:~P~-{>}~Q~-{>}~R\\
+  ~~q~:~Q\\
+  ~~p~:~P\\
+  ~~============================\\
+  ~~~\textcolor{blue}{Q}\\
+  \medskip
+  \textup{Coq~{<}~~~assumption.}}
+\only<13>{%
+  \textup{Coq~{<}~~~assumption.}\\
+  Proof~completed.\\
+  \medskip
+  \textup{Coq~{<}}}
+\only<14>{%
+  \textup{Coq~{<}~~~assumption.}\\
+  Proof~completed.\\
+  \medskip
+  \textup{Coq~{<}~Qed.}}
+\only<15>{%
+  \textup{Coq~{<}~Qed.}\\
+  intro~H.\\
+  intro~q.\\
+  intro~p.\\
+  apply~H.\\
+  assumption.\\
+  assumption.\\
+  imp\_perm~is~defined\\
+  \medskip
+  \textup{Coq~{<}~}}
+\end{overlayarea}
+\end{block}
+\begin{block}{}
+%
+% derivation tree
+%
+\begin{overprint}
+\begin{gather*}
+\only<1-2>	{\drv{coq-sample.0}}
+\only<3-4>	{\drv{coq-sample.1}}
+\only<5-6>	{\drv{coq-sample.2}}
+\only<7-8>	{\drv{coq-sample.3}}
+\only<9-10>	{\drv{coq-sample.4}}
+\only<11-12>	{\drv{coq-sample.5}}
+\only<13-15>	{\drv{coq-sample.6}}
+\end{gather*}
+\end{overprint}
+\end{block}
+\end{frame}
+\end{document}
diff --git a/Master/texmf-dist/doc/metapost/drv/sample/drv.mp b/Master/texmf-dist/doc/metapost/drv/sample/drv.mp
new file mode 100644
index 00000000000..5eb38396144
--- /dev/null
+++ b/Master/texmf-dist/doc/metapost/drv/sample/drv.mp
@@ -0,0 +1,2245 @@
+%% drv.mp 0.93
+%% Copyright 2009 Laurent M\'ehats
+%
+% This work may be distributed and/or modified under the
+% conditions of the LaTeX Project Public License, either version 1.3
+% of this license or (at your option) any later version.
+% The latest version of this license is in
+%   http://www.latex-project.org/lppl.txt
+% and version 1.3 or later is part of all distributions of LaTeX
+% version 2005/12/01 or later.
+%
+% This work has the LPPL maintenance status `maintained'.
+%
+% The Current Maintainer of this work is Laurent M\'ehats.
+% <laurent.mehats@gmail.com>
+%
+% This work consists of the file drv.mp
+
+
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+%
+% User's macros summary
+%
+%
+% * Judgment & inference declarations
+% ===================================
+%
+%   jgm <nat> <str list>
+%	<nat>		judgment index
+%	<str list>	sub-judgments math-mode LaTeX code
+%
+%   nfr <nat> (<nat list>) (<str>, <id>)
+%	<nat>		inference index
+%	<nat list>	list of premise indices
+%	<str>		inference label math-mode LaTeX code
+%	<id>		inference line style identifier
+%			(0, 1, 2, 3, 4, 5, 6 or _)
+%			  0	none
+%			  1	simple
+%			  2	double
+%			  3	dotted
+%			  4	dashed
+%			  5	waved
+%			  6	TeX-dotted
+%			  _	default (set by drv_path_style)
+%
+%   mvd <nat 1> (<nat 2>, <id>)
+%	<nat 1>		index of the origin judgment
+%	<nat 2>		number of phantom steps
+%	<id>		phantom steps path-style identifier
+%			(0, 1, 2, 3, 4, 5, 6 or _)
+%
+%   Nfr <nat> (<nat list>) (<str 1>, <str 2>, <str 3>, <id>)
+%	<nat>		inference index
+%	<nat list>	list of premise indices
+%	<str 1>		inference label math-mode LaTeX code
+%	<str 2>		left delimiter label math-mode LaTeX code
+%	<str 3>		right delimiter label math-mode LaTeX code
+%	<id>		inference line style identifier
+%			(0, 1, 2, 3, 4, 5, 6 or _)
+%
+%   Mvd <nat 1> (<nat 2>, <str 1>, <str 2>, <id>)
+%	<nat 1>		index of the origin judgment
+%	<nat 2>		number of phantom steps
+%	<str 1>		left label math-mode LaTeX code
+%	<str 2>		right label math-mode LaTeX code
+%	<id>		phantom steps path-style identifier
+%			(0, 1, 2, 3, 4, 5, 6 or _)
+%
+%   NFR <nat> (<nat list>) (<str 1>, <str 2>, <str 3>, <str 4>)
+%     (<id 1>, <id 2>, <id 3>)
+%	<nat>		inference index
+%	<nat list>	list of premise indices
+%	<str 1>		left inference label math-mode LaTeX code
+%	<str 2>		right inference label math-mode LaTeX code
+%	<str 3>		left delimiter label math-mode LaTeX code
+%	<str 4>		right delimiter label math-mode LaTeX code
+%	<id 1>		junction style identifier (0, 1, 2, 3 or _)
+%			  0	fully-interlacing
+%			  1	semi-interlacing
+%			  2	non-interlacing
+%			  3	user specified (tricky)
+%			  _	default (set by drv_junction_style)
+%	<id 2>		alignment style identifier (l, c, r, u or _)
+%			  l	left
+%			  c	centered
+%			  r	right
+%			  u	user specified (tricky)
+%			  _	default (set by drv_alignment_style)
+%	<id 3>		inference line style identifier
+%			(0, 1, 2, 3, 4, 5, 6 or _)
+%
+%   MVD <nat 1> (<nat 2>, <str 1>, <str 2>, <id 1> <id 2>)
+%	<nat 1>		index of the origin judgment
+%	<nat 2>		number of phantom steps
+%	<str 1>		left label math-mode LaTeX code
+%	<str 2>		right label math-mode LaTeX code
+%	<id 1>		alignment style identifier (l, c, r, u or _)
+%	<id 2>		phantom steps path-style identifier
+%			(0, 1, 2, 3, 4, 5, 6 or _)
+%
+%   NFR_opt <nat> (<nat list>) (<str list 1>) (<str list 2>)
+%     (<id 1>, <id 2>, <id 3>)
+%	<nat>		inference index
+%	<nat list>	list of premise indices
+%	<str list 1>	list of inference labels math-mode LaTeX code
+%	<str list 2>	list of delimiter labels math-mode LaTeX code
+%	<id 1>		junction style identifier (0, 1, 2, 3 or _)
+%	<id 2>		alignment style identifier (l, c, r, u or _)
+%	<id 3>		inference line style identifier
+%			(0, 1, 2, 3, 4, 5, 6 or _)
+%
+%   MVD_opt <nat 1> (<nat 2>) (<str list>) (<id 1> <id 2>)
+%	<nat 1>		index of the origin judgment
+%	<nat 2>		number of phantom steps
+%	<str list>	list of labels math-mode LaTeX code
+%	<id 1>		alignment style identifier (l, c, r or u)
+%	<id 2>		phantom steps path-style identifier
+%			(0, 1, 2, 3, 4, 5, 6 or _)
+%
+% * Tunings
+% =========
+%
+%   drv_font_size <str>
+%	<str>		LaTeX font-size command
+%			  "\tiny"
+%			  "\scriptsize"
+%			  "\footnotesize"
+%			  "\small"
+%			  "\normalsize"
+%			  "\large"
+%			  "\Large"
+%			  etc.
+%
+%   drv_math_style (<id>, <str>)
+%	<id>		component identifier (drv, jdg, ilb, dlb or plb)
+%			  drv	derivation trees
+%			  jdg	judgments
+%			  ilb	inference labels
+%			  dlb	delimiter labels
+%			  plb	phantom steps labels
+%	<str>		LaTeX math-style command
+%
+%   drv_scale (<id>, <float>)
+%	<id>		scale identifier (clr, prm, jdg or ilb)
+%			  clr	nice explanation soon (see examples)
+%			  prm	nice explanation soon (see examples)
+%			  jdg	nice explanation soon (see examples)
+%			  ilb	nice explanation soon (see examples)
+%	<float>		scale value
+%
+%   drv_junction_style <id>
+%	<id>		junction style identifier (0, 1 or 2)
+%			  0	``fully-interlacing''
+%			  1	``semi-interlacing''
+%			  2	``non-interlacing''
+%
+%   drv_alignment_style <id>
+%	<id>		alignment style identifier (l, c or r)
+%			  l	left
+%			  c	centered
+%			  r	right
+%
+%   drv_path_style (<id 1>, <id 2>)
+%	<id 1>		path-type identifier (iln or phm)
+%			  iln	inference lines
+%			  phm	phantom steps paths
+%	<id 2>		path-style identifier (0, 1, 2, 3, 4, 5 or 6)
+%
+%   drv_labels_position (<id 1>, <id 2>)
+%	<id 1>		label-type identifier (ilb, plb or dlb)
+%			  ilb	inference labels
+%			  dlb	delimiter labels
+%			  plb	phantom steps labels
+%	<id 2>		position identifier (l or r)
+%			  l	left
+%			  r	right
+%
+%   drv_roots_position <id>
+%	<id>		position identifier (t or b)
+%			  t	top
+%			  b	bottom
+%
+%   drv_axis_reference <id>
+%	<id>		reference identifier (iln or jdg)
+%			  iln	root inference line axis
+%			  jdg	root judgment math-axis
+%
+%   drv_left_delimiter <str>
+%	<str>		left delimiter math-mode LaTeX code
+%			  "("	$($
+%			  "["	$[$
+%			  "\lbrace"	$\lbrace$
+%			  "\langle"	$\langle$
+%			  etc.
+%
+%   drv_right_delimiter <str>
+%	<str>		right delimiter math-mode LaTeX code
+%			  ")"
+%			  "]"
+%			  "\rbrace"
+%			  "\rangle"
+%			  etc.
+%
+%   drv_box_mode <id>
+%	<id>		status identifier (on or off)
+%			  on
+%			  off
+%
+%   drv_fraction_mode <id>
+%	<id>		status identifier (on or off)
+%			  on
+%			  off
+%
+%   drv_proof_mode <id>
+%	<id>		status identifier (on or off)
+%			  on
+%			  off
+%
+% * Derivation tree pictures
+% ==========================
+%
+%   drv_bbox <nat>
+%	<nat>		sub-tree root index
+%
+%   drv_axis (<id>, <nat>)
+%	<id>		reference type identifier (iln, jdg or dlm)
+%			  iln	inference line axis
+%			  jdg	judgment math-axis
+%			  dlm	delimiter axis
+%	<nat>		reference index
+%
+%   <path> drv_styled <id>
+%	<path>		MetaPost path expression
+%	<id>		path style identifier (0, 1, 2, 3, 4, 5 or 6)
+%
+
+
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+%
+% MetaPost messages formatting
+%
+
+% drv_format prevents messages from being automatically cut into lines every
+% 79 characters: if possible, a word which would otherwise be cut is 'pushed'
+% to the following line by inserting space characters before it.
+
+vardef drv_format (expr str, fst_len, nxt_len, dbl_pcs)=
+  % str: the message to be formatted
+  % fst_len: first line length
+  % nxt_len: following lines length
+  % dbl_pcs (boolean): occurrences of the percent character must be doubled
+  save str_len, sub_len, aux_len, chr_rnk, occ_num;
+  numeric str_len, sub_len, aux_len, chr_rnk, occ_num;
+  save aux_str, chr;
+  string aux_str, chr;
+  str_len:=length str;
+  sub_len:=0;
+  chr_rnk:=0;
+  occ_num:=0;
+  aux_len:=0;
+  aux_str:="";
+  forever:
+    exitif (chr_rnk=fst_len) or (chr_rnk=str_len);
+    chr:=substring (chr_rnk, chr_rnk+1) of str;
+    aux_str:=aux_str&chr;
+    if chr=" ":
+      sub_len:=chr_rnk+1;
+      aux_len:=sub_len+occ_num;
+    elseif (chr="%") and dbl_pcs:
+      aux_str:=aux_str&"%";
+      occ_num:=occ_num+1;
+    fi
+    chr_rnk:=chr_rnk+1;
+  endfor
+  if chr_rnk=fst_len:
+    begingroup
+      if sub_len=0:
+        sub_len:=fst_len;
+        aux_len:=sub_len+occ_num;
+      fi
+      substring (0, aux_len) of aux_str&
+        for idx=sub_len+1 upto fst_len:
+          " "&
+        endfor
+        drv_format (substring (sub_len, str_len) of str,
+          nxt_len, nxt_len, dbl_pcs)
+    endgroup
+  else:
+    aux_str
+  fi
+enddef;
+
+boolean drv_inside_fig;
+drv_inside_fig:=false;
+
+vardef drv_context=
+  "drv"&if drv_inside_fig: " (fig. "&decimal charcode&")"&fi ": "
+enddef;
+
+vardef drv_message expr str=
+  message drv_format (drv_context&str, 79, 79, false);
+enddef;
+
+vardef drv_errhelp expr str=
+  % Occurrences of the percent character must be doubled: errhelp makes single
+  % single occurrences behave as newline characters (this is inherited from
+  % MetaFont).
+  errhelp drv_format (str, 79, 79, true);
+enddef;
+
+vardef drv_errmessage expr str=
+  % errmessage inserts the 2-characters string  "! " before its argument.
+  % Hence 77 as a first line length argument.
+  errmessage drv_format (drv_context&str, 77, 79, false);
+enddef;
+
+
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+%
+% Delayed LaTeX processing
+%
+
+picture tex_pct[];
+string delayed_tex_file;
+delayed_tex_file:=jobname&"-delayed.mp";
+
+%
+% reading LaTeX picture definitions
+%
+
+boolean drv_nullpicture;
+drv_nullpicture:=true;
+
+string readfrom_str;
+readfrom_str:=readfrom delayed_tex_file;
+if readfrom_str<>EOF:
+  closefrom delayed_tex_file;
+  drv_message ("reading `"&delayed_tex_file&"' LateX picture definitions.");
+  batchmode;
+  scantokens ("input "&delayed_tex_file);
+  errorstopmode;
+  drv_message "done.";
+  drv_nullpicture:=false;
+fi
+
+%
+% copying LaTeX preamble
+%
+
+vardef drv_read (expr search_str) (suffix accum_str)=
+  save readfrom_str, readfrom_substr;
+  string readfrom_str, readfrom_substr;
+  accum_str:="";
+  forever:
+    readfrom_str:=readfrom jobname;
+    readfrom_substr:=substring (0, length search_str) of readfrom_str;
+    exitif (readfrom_substr=search_str) or (readfrom_str=EOF);
+    accum_str:=accum_str&readfrom_str&char(10);
+  endfor
+  if readfrom_str=EOF:
+    closefrom jobname;
+    drv_errhelp ("`"&jobname&".mp' should contain a line starting with "&
+      ditto&search_str&ditto&".");
+    drv_errmessage (ditto&search_str&ditto&" is missing");
+  fi
+enddef;
+
+string tex_preamble_str[];
+% tex_preamble_str[0] from "verbatimtex %&latex" to "\begin{document}"
+% tex_preamble_str[1] from "\begin{document}" to "etex;"
+
+drv_message ("reading `"&jobname&".mp' LateX preamble.");
+  drv_read ("verbatimtex %&latex", tex_preamble_str[0]);
+  drv_read ("\begin{document}", tex_preamble_str[0]);
+  drv_read ("etex;", tex_preamble_str[1]);
+  closefrom jobname;
+  write
+    "%"&char(10)&
+    "% AUTOMATICALLY GENERATED BY DRV.MP - DO NOT MODIFY."&char(10)&
+    "%"&char(10)&char(10)&
+    "verbatimtex %&latex"&char(10)&
+    tex_preamble_str[0]&
+    "\begin{document}"&char(10)&
+    tex_preamble_str[1]&
+    "etex;"
+  to delayed_tex_file;
+drv_message "done.";
+
+%
+% writing LaTeX picture definitions
+%
+
+numeric tex_pct_idx;
+tex_pct_idx:=0;
+
+% Math style indices: 0, 1, 2, 3
+string mth_sty_str[];
+mth_sty_str[0]:="\displaystyle";
+mth_sty_str[1]:="\textstyle";
+mth_sty_str[2]:="\scriptstyle";
+mth_sty_str[3]:="\scriptscriptstyle";
+
+string drv_fontsize;
+
+vardef drv_tex[] expr tex_str=
+  % @: math style index
+  % tex_str: math mode LaTeX code
+  save def_str, pct;
+  string def_str;
+  picture pct;
+  def_str:="btex{"&drv_fontsize&"$"&mth_sty_str[@]&"{}"&tex_str&"{}$}etex;";
+  write "tex_pct["&(decimal tex_pct_idx)&"]:="&def_str to delayed_tex_file;
+  pct:=
+    if known tex_pct[tex_pct_idx]:
+      tex_pct[tex_pct_idx]
+    else:
+      nullpicture
+    fi;
+  tex_pct_idx:=tex_pct_idx+1;
+  pct
+enddef;
+
+
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+%
+% MetaPost shorthands
+%
+
+vardef depth expr pct=
+  ypart llcorner pct
+enddef;
+
+vardef height expr pct=
+  ypart urcorner pct
+enddef;
+
+vardef width expr pct=
+  xpart urcorner pct-xpart llcorner pct
+enddef;
+
+
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+%
+% Font-specific parameters
+%
+
+%
+% em[s]		width of an m (s: mathstyle index)
+% ex[s]		height of an x
+% axis_hg[s]	height of the mathematical axis
+% num_bl_hg[s]	height of a numerator baseline w.r.t. the fraction bar axis
+% den_bl_dp[s]	depth of a denominator baseline w.r.t. the fraction bar axis
+% rul_thk[s]	default rule thickness
+%
+
+numeric em[], ex[], axis_hg[], num_bl_hg[], den_bl_dp[], rul_thk[];
+
+%
+% thn_sp[s]	thin space, usually 1em/6
+% med_sp[s]	medium space, usually 2em/9
+% thk_sp[s]	thick space, usually 5em/18
+%
+
+numeric thn_sp[], med_sp[], thk_sp[];
+
+%
+% pdt_hg[s]	height of a punctuation ldot
+% pdt_wd[s]	width of a punctuation ldot
+%
+
+numeric pdt_hg[], pdt_wd[];
+
+%
+% tt_dgt[s][i]	typewriter typeface digits (i ranges from 0 to 9)
+%
+
+picture tt_dgt[][];
+
+%
+% min_clr[s]	minimal clearance between a numerator
+%		or a denominator and the fraction bar
+% prm_skp[s]	<nice explanation>
+% jdg_skp[s]	<nice explanation>
+% ilb_skp[s]	<nice explanation>
+% plb_skp[s]	<nice explanation>
+%
+
+numeric min_clr[], prm_skp[], jdg_skp[], ilb_skp[], plb_skp[];
+
+vardef drv_fontdimen[] expr font=
+  save dim_pct;
+  picture dim_pct;
+  dim_pct:=drv_tex[0] ("\rule{\the\fontdimen"&(decimal @)&font&"}{0bp}");
+  width dim_pct
+enddef;
+
+vardef drv_font_size expr size_str=
+  save pdt_pct, sp_pct;
+  picture pdt_pct, sp_pct;
+  drv_fontsize:=size_str;
+  write char(10)&"% font-specific parameters ("&drv_fontsize&")"&char(10)
+    to delayed_tex_file;
+  ex[0]:=drv_fontdimen[5] "\textfont2";
+  ex[1]:=drv_fontdimen[5] "\textfont2";
+  ex[2]:=drv_fontdimen[5] "\scriptfont2";
+  ex[3]:=drv_fontdimen[5] "\scriptscriptfont2";
+  em[0]:=drv_fontdimen[6] "\textfont2";
+  em[1]:=drv_fontdimen[6] "\textfont2";
+  em[2]:=drv_fontdimen[6] "\scriptfont2";
+  em[3]:=drv_fontdimen[6] "\scriptscriptfont2";
+  rul_thk[0]:=drv_fontdimen[8] "\textfont3";
+  rul_thk[1]:=drv_fontdimen[8] "\textfont3";
+  rul_thk[2]:=drv_fontdimen[8] "\scriptfont3";
+  rul_thk[3]:=drv_fontdimen[8] "\scriptscriptfont3";
+  axis_hg[0]:=drv_fontdimen[22] "\textfont2";
+  axis_hg[1]:=drv_fontdimen[22] "\textfont2";
+  axis_hg[2]:=drv_fontdimen[22] "\scriptfont2";
+  axis_hg[3]:=drv_fontdimen[22] "\scriptscriptfont2";
+  num_bl_hg[0]:=(drv_fontdimen[8] "\textfont2")-axis_hg[0];
+  num_bl_hg[1]:=(drv_fontdimen[9] "\textfont2")-axis_hg[1];
+  num_bl_hg[2]:=(drv_fontdimen[9] "\scriptfont2")-axis_hg[2];
+  num_bl_hg[3]:=(drv_fontdimen[9] "\scriptscriptfont2")-axis_hg[3];
+  den_bl_dp[0]:=-(drv_fontdimen[11] "\textfont2")-axis_hg[0];
+  den_bl_dp[1]:=-(drv_fontdimen[12] "\textfont2")-axis_hg[1];
+  den_bl_dp[2]:=-(drv_fontdimen[12] "\scriptfont2")-axis_hg[2];
+  den_bl_dp[3]:=-(drv_fontdimen[12] "\scriptscriptfont2")-axis_hg[3];
+  min_clr[0]:=3*rul_thk[0]; % The TEXbook,
+  min_clr[1]:=1*rul_thk[1]; % Appendix G,
+  min_clr[2]:=1*rul_thk[2]; % Rule 15d.
+  min_clr[3]:=1*rul_thk[3]; %
+  for mth_sty:=0 upto 3:
+    sp_pct:=drv_tex[mth_sty] "\,";
+    thn_sp[mth_sty]:=width sp_pct;
+    sp_pct:=drv_tex[mth_sty] "\>";
+    med_sp[mth_sty]:=width sp_pct;
+    sp_pct:=drv_tex[mth_sty] "\;";
+    thk_sp[mth_sty]:=width sp_pct;
+    pdt_pct:=drv_tex[mth_sty] "\ldotp";
+    pdt_hg[mth_sty]:=height pdt_pct;
+    pdt_wd[mth_sty]:=width pdt_pct;
+    for dgt=0 upto 9:
+      tt_dgt[mth_sty][dgt]:=drv_tex[mth_sty] "\texttt{"&(decimal dgt)&"}";
+    endfor
+    prm_skp[mth_sty]:=3*med_sp[mth_sty]; % arbitrary
+    jdg_skp[mth_sty]:=thn_sp[mth_sty];   % arbitrary
+    ilb_skp[mth_sty]:=thn_sp[mth_sty];   % arbitrary
+    plb_skp[mth_sty]:=thk_sp[mth_sty];   % arbitrary
+  endfor
+enddef;
+
+
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+%
+% Math-related parameters & macros
+%
+
+%
+% Math styles
+% drv_sty		derivation trees
+% jdg_sty[drv_sty]	judgments
+% ilb_sty[drv_sty]	inference labels
+% dlb_sty[drv_sty]	delimiter labels
+% plb_sty[drv_sty]	phantom steps labels
+%
+
+numeric drv_sty, jdg_sty[], ilb_sty[], dlb_sty[], plb_sty[];
+
+%
+% Math-axis centered LaTeX pictures
+%
+
+vardef mth_tex[] expr tex_str=
+  (drv_tex[@] tex_str) shifted (0, -axis_hg[@])
+enddef;
+
+
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+%
+% drv-boxes
+%
+
+vardef drv_box text STR=
+  for str=STR:
+    expandafter picture scantokens str;
+    expandafter pair scantokens str.l;
+    expandafter pair scantokens str.c;
+    expandafter pair scantokens str.r;
+    expandafter numeric scantokens str.hg;
+    expandafter numeric scantokens str.dp;
+  endfor
+enddef;
+
+vardef box_init @# (expr pct)=
+  @#:=pct;
+  @#.r-@#.l=(width pct, 0);
+  @#.c=(@#.l+@#.r)/2;
+  @#.hg:=height pct;
+  @#.dp:=depth pct;
+enddef;
+
+vardef box_freeze @#=
+  @#:=@# shifted @#.l;
+enddef;
+
+
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+%
+% beginfig & endfig
+%
+
+%
+% drv_beginfig: figure initialization
+%
+
+pen drv_pen;
+
+vardef drv_beginfig=
+  %
+  % Judgments
+  %
+  % jdg[i]	judgment drv-box
+  % sbj_num[i]	number of sub-judgments
+  % sbj[i][j]	sub-judgment drv-box (j ranges from 0 to sbj_num[i]-1)
+  %
+  drv_box "jdg[]";
+  numeric sbj_num[];
+  drv_box "sbj[][]";
+  %
+  % Inferences
+  %
+  % prm_num[i]	number of premises
+  % prm[i][j]	premise index (j ranges from 0 to prm_num[i]-1)
+  % ccl[i]	conclusion index
+  % jct_sty[i]	junction style
+  % alg_sty[i]	alignment style
+  % iln_sty[i]	inference line style
+  % l_prm[i]	leftmost `graphical' premise index
+  % r_prm[i]	rightmost `graphical' premise index
+  %
+  numeric prm_num[], prm[][], ccl[];
+  numeric jct_sty[];
+  string alg_sty[];
+  numeric iln_sty[];
+  numeric l_prm[], r_prm[];
+  %
+  % imin_x[i]	inference minimal x
+  % l_dlb[i]	left delimiter label drv-box
+  % l_dlm[i]	left delimiter drv-box
+  % l_ilb[i]	left label drv-box
+  % iln[i]	inference line drv-box
+  % r_ilb[i]	right label drv-box
+  % r_dlm[i]	right delimiter drv-box
+  % r_dlb[i]	right delimiter label drv-box
+  % imax_x[i]	inference maximal x
+  %
+  numeric imin_x[];
+  drv_box "l_dlb[]", "l_dlm[]", "l_ilb[]";
+  drv_box "iln[]";
+  drv_box "r_ilb[]", "r_dlm[]", "r_dlb[]";
+  numeric imax_x[];
+  %
+  % Sub-trees
+  %
+  % smin_x[i]	sub-tree minimal x
+  % smax_x[i]	sub-tree maximal x
+  % smin_y[i]	sub-tree minimal y
+  % smax_y[i]	sub-tree maximal y
+  % boxed[i]	boolean
+  %
+  numeric smin_x[], smax_x[], smin_y[], smax_y[];
+  boolean boxed[];
+  %
+  % Pen initialization
+  %
+  drv_pen:=pencircle scaled rul_thk[drv_sty];
+  %
+  % num_hg	height of a numerator axis w.r.t. the fraction bar axis
+  % den_dp	depth of a denominator axis w.r.t. the fraction bar axis
+  % iln_hg[s]	height of a style s inference line
+  % iln_dp[s]	depth of a style s inference line
+  %
+  numeric num_hg, den_dp, iln_hg[], iln_dp[];
+  num_hg:=num_bl_hg[drv_sty]+axis_hg[jdg_sty[drv_sty]];
+  den_dp:=den_bl_dp[drv_sty]+axis_hg[jdg_sty[drv_sty]];
+  picture iln_pct;
+  for sty=0 upto 6:
+    iln_pct:=((0, 0)--(10, 0)) drv_styled sty;
+    iln_hg[sty]:=height iln_pct;
+    iln_dp[sty]:=depth iln_pct;
+  endfor
+  %
+  % Derivation trees
+  %
+  % root_num	number of roots
+  % root[i]	root index (i ranges from 0 to root_num-1)
+  % drv_built	boolean
+  % drv_frozen	boolean
+  %
+  numeric root_num, root[];
+  boolean drv_checked, drv_built, drv_frozen;
+  root_num:=0;
+  drv_checked:=false;
+  drv_built:=false;
+  drv_frozen:=false;
+  %
+  % Phantom steps
+  %
+  % phm_idx	phantom inferences index
+  % src[i]	base phantom judgment index (in case of an origin judgment)
+  % tgt[i]	origin judgment index (in case of a base phantom judgment)
+  % phm_sty[i]	phantom steps style
+  % l_plb[i]	left phantom steps label drv-box (in case of a base
+  %		phantom judgment)
+  % phm[i]	phantom steps drv-box (in case of a base phantom
+  %		judgment)
+  % r_plb[i]	right phantom steps label drv-box (in case of a base
+  %		phantom judgment)
+  %
+  numeric phm_idx, src[], tgt[], phm_sty[];
+  phm_idx:=0;
+  drv_box "l_plb[]", "phm[]", "r_plb[]";
+  %
+  % Proof pictures
+  %
+  % jdg_prf[i]		judgment index drv-box
+  % sbj_prf[i][j]	sub-judgment index drv-box (j ranges from 0 to
+  %			sbj_num[i]-1)
+  %
+  drv_box "jdg_prf[]", "sbj_prf[][]";
+  %
+  % Info
+  %
+  write char(10)&"% fig. "&(decimal charcode)&char(10) to delayed_tex_file;
+  drv_inside_fig:=true; % context: inside a figure
+enddef;
+
+extra_beginfig:=extra_beginfig&"drv_beginfig;";
+
+%
+% drv_endfig: proof-file generation
+%
+
+string proof_file;
+proof_file:=jobname&"-proof.tex";
+
+% TODO: taking outputtemplate into account.
+vardef output_file[]=
+  jobname&"."&(decimal @)
+enddef;
+
+string buf_str;
+buf_str:=
+  "%"&char(10)&
+  "% AUTOMATICALLY GENERATED BY DRV.MP."&char(10)&
+  "%"&char(10)&char(10)&
+  tex_preamble_str[0]&
+  "\usepackage{graphicx}"&char(10)&
+  "\makeatletter"&char(10)&
+  "\def\Gin@def@bp#1\relax#2#3{\gdef#2{#3}}"&char(10)&
+  "\newsavebox{\graphicsbox}"&char(10)&
+  "\newcommand*{\drv}[1]{%"&char(10)&
+  "\sbox{\graphicsbox}{\includegraphics{#1}}%"&char(10)&
+  "\raisebox{\Gin@lly bp}%"&char(10)&
+  "{\usebox{\graphicsbox}}}"&char(10)&
+  "\makeatother"&char(10)&char(10)&
+  "\newcount\h"&char(10)&
+  "\newcount\m"&char(10)&
+  "\h=\time"&char(10)&
+  "\divide\h 60"&char(10)&
+  "\m=-\h"&char(10)&
+  "\multiply\m 60"&char(10)&
+  "\advance\m\time"&char(10)&
+  "\def\hm{\number\h:\ifnum\m<10{}0\fi\number\m}"&char(10)&char(10)&
+  "\newcommand{\mathaxis}{\frac{\quad}{}}"&char(10)&char(10)&
+  "\begin{document}"&char(10)&
+  tex_preamble_str[1]&
+  "\noindent\today\ at \hm\medskip"&char(10)&char(10)&"\noindent";
+
+vardef drv_endfig=
+  drv_inside_fig:=false;   % context: outside a figure
+  buf_str:=buf_str&char(10)&
+  "\texttt{"&output_file[charcode]&"}"&char(10)&
+  "  (\verb+"&drv_fontsize&"+, \verb+"&(mth_sty_str[drv_sty])&"+)"&char(10)&
+  "    {"&drv_fontsize&char(10)&
+  "      \["&(mth_sty_str[drv_sty])&char(10)&
+  "        \mathaxis\drv{"&output_file[charcode]&"}\mathaxis"&char(10)&
+  "      \]}\\";
+  write EOF to proof_file; % erases the previous content
+  write buf_str&char(10)&"\end{document}" to proof_file;
+  write EOF to proof_file;
+  if drv_nullpicture:
+    draw btex{\tt drv}: run {\tt mpost} again.etex withcolor (1, 0, 0);
+  fi
+enddef;
+
+extra_endfig:="drv_endfig;"&extra_endfig;
+
+
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+%
+% Judgment declarations
+%
+
+vardef jgm[] text SUB=
+  % @: judgment index
+  % SUB: list of `sub-judgments' (pictures or strings)
+  if @<0:
+    drv_errhelp "An judgment index can not be negative.";
+    drv_errmessage (decimal @)&" is negative";
+  elseif known jdg[@]:
+    drv_errhelp "An index can be used only once to declare a judgment.";
+    drv_errmessage (decimal @)&" has been used already as a judgment index";
+  else:
+    save jdg_pct, sbj_pct, jdg_wd, sbj_rnk;
+    picture jdg_pct, sbj_pct;
+    numeric jdg_wd, sbj_rnk;
+    jdg_pct:=nullpicture;
+    jdg_wd:=0;
+    sbj_rnk:=0;
+    for sub=SUB:
+      sbj_pct:=
+        if picture sub:
+          sub
+        elseif sub<>"":
+          mth_tex[jdg_sty[drv_sty]] sub
+        else:
+          nullpicture
+        fi;
+      box_init sbj[@][sbj_rnk] (sbj_pct);
+      if sbj_rnk>0:
+        sbj[@][sbj_rnk-1].r=sbj[@][sbj_rnk].l;
+      fi
+      addto jdg_pct also sbj_pct shifted (jdg_wd, 0);
+      jdg_wd:=width jdg_pct;
+      sbj_rnk:=sbj_rnk+1;
+    endfor
+    sbj_num[@]:=sbj_rnk;
+    box_init jdg[@] (jdg_pct);
+    if sbj_num[@]>0:
+      jdg[@].l=sbj[@][0].l;
+      jdg[@].r=sbj[@][sbj_num[@]-1].r;
+    fi
+  fi
+enddef;
+
+
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+%
+% Inference declarations
+%
+
+vardef check_junction_style (suffix sty_sfx) (expr default)=
+  save sty_str;
+  string sty_str;
+  sty_str:=str sty_sfx;
+  if (sty_str="0")
+  or (sty_str="1")
+  or (sty_str="2")
+  or (sty_str="3"):
+    sty_sfx
+  elseif (sty_str="_"):
+    default
+  else:
+    begingroup
+      drv_errhelp "Valid identifiers are"&
+        " 0 (fully-interlacing),"&
+        " 1 (semi-interlacing),"&
+        " 2 (non-interlacing),"&
+        " 3 (user specified) and"&
+        " _ (default).";
+      drv_errmessage sty_str&" is not a valid junction style identifier";
+      default
+    endgroup
+  fi
+enddef;
+
+vardef check_alignment_style (suffix sty_sfx) (expr default)=
+  save sty_str;
+  string sty_str;
+  sty_str:=str sty_sfx;
+  if (sty_str="l")
+  or (sty_str="c")
+  or (sty_str="r")
+  or (sty_str="u"):
+    sty_str
+  elseif (sty_str="_"):
+    default
+  else:
+    begingroup
+      drv_errhelp "Valid identifiers are"&
+        " l (none),"&
+        " c (simple),"&
+        " r (double),"&
+        " u (dotted) and"&
+        " _ (default).";
+      drv_errmessage sty_str&" is not a valid alignment style identifier";
+      default
+    endgroup
+  fi
+enddef;
+
+vardef check_path_style (suffix sty_sfx) (expr default)=
+  save sty_str;
+  string sty_str;
+  sty_str:=str sty_sfx;
+  if (sty_str="0")
+  or (sty_str="1")
+  or (sty_str="2")
+  or (sty_str="3")
+  or (sty_str="4")
+  or (sty_str="5")
+  or (sty_str="6"):
+    sty_sfx
+  elseif (sty_str="_"):
+    default
+  else:
+    begingroup
+      drv_errhelp "Valid identifiers are"&
+        " 0 (none),"&
+        " 1 (simple),"&
+        " 2 (double),"&
+        " 3 (dotted),"&
+        " 4 (dashed),"&
+        " 5 (waved),"&
+        " 6 (TeX-dotted) and"&
+        " _ (default).";
+      drv_errmessage sty_str&" is not a valid path style identifier";
+      default
+    endgroup
+  fi
+enddef;
+
+vardef opt_init[] @# expr arg=
+  if picture arg:
+    if arg<>nullpicture:
+      box_init @# (arg);
+    fi
+  elseif arg<>"":
+    box_init @# (mth_tex[@] arg);
+  fi
+enddef;
+
+vardef NFR[] (text PRM) (expr lilb, rilb, ldlb, rdlb)
+  (suffix j_sty, a_sty, i_sty)=
+  %
+  % @: inference index
+  %
+  if known prm_num[@]:
+    drv_errhelp "An index can be used only once to declare an inference.";
+    drv_errmessage (decimal @)&" has been used already as an inference index";
+  else:
+    %
+    % PRM: list of premise indices
+    %
+    save prm_rnk;
+    numeric prm_rnk;
+    prm_rnk:=0;
+    for prm_idx=PRM:
+      if prm_idx=@:
+        drv_errhelp "An inference index can not be used"&
+          " as one of its own premise indices.";
+        drv_errmessage "the inference index "&(decimal prm_idx)&
+          " is used as one of its own premise indices";
+      elseif known ccl[prm_idx]:
+        drv_errhelp "An index can be used only once as a premise index.";
+        drv_errmessage (decimal prm_idx)&" has been used already as a"&
+          " premise index for inference declaration "&(decimal ccl[prm_idx]);
+      else:
+        if known prm_num[prm_idx]:
+          %
+          % roots list update
+          %
+          save root_idx;
+          numeric root_idx;
+          root_idx:=0;
+          forever:
+            exitif root[root_idx]=prm_idx;
+            root_idx:=root_idx+1;
+          endfor
+          forever:
+            exitif root_idx=root_num-1;
+            root[root_idx]:=root[root_idx+1];
+            root_idx:=root_idx+1;
+          endfor
+          root_num:=root_num-1;
+        fi
+        ccl[prm_idx]:=@;
+        prm[@][prm_rnk]:=prm_idx;
+        prm_rnk:=prm_rnk+1;
+      fi
+    endfor
+    prm_num[@]:=prm_rnk;
+    if known ccl[@]:
+      %
+      % cycle detection
+      %
+      save ccl_idx, ccl_str;
+      numeric ccl_idx;
+      string ccl_str;
+      ccl_idx:=@;
+      ccl_str:=decimal ccl_idx;
+      forever:
+        ccl_idx:=ccl[ccl_idx];
+        if ccl_idx>=0:
+          ccl_str:=(decimal ccl_idx)&", "&ccl_str;
+        fi
+        exitif (unknown ccl[ccl_idx]) or (ccl_idx=@);
+      endfor
+      if ccl_idx=@:
+        drv_errhelp  "Inferences declarations can not be cyclic.";
+        drv_errmessage "inference declaration "&(decimal @)&" creates a"&
+          " cycle of inferences (indices "&ccl_str&" from conclusions to"&
+          " premises)";
+      fi
+    else:
+      root[root_num]:=@;
+      root_num:=root_num+1;
+    fi
+    %
+    % lilb, rilb: inference labels
+    %
+    opt_init[ilb_sty[drv_sty]] l_ilb[@] lilb;
+    opt_init[ilb_sty[drv_sty]] r_ilb[@] rilb;
+    %
+    % ldlb, rdlb: delimiter labels
+    %
+    opt_init[dlb_sty[drv_sty]] l_dlb[@] ldlb;
+    opt_init[dlb_sty[drv_sty]] r_dlb[@] rdlb;
+    %
+    % j_sty, a_sty and i_sty: junction, alignment and inference styles
+    %
+    jct_sty[@]:=check_junction_style (j_sty, drv_jct_sty);
+    alg_sty[@]:=check_alignment_style (a_sty, drv_alg_sty);
+    iln_sty[@]:=check_path_style (i_sty, drv_iln_sty);
+    if drv_boxmode_on:
+      boxed[@]:=true;
+    fi
+  fi
+enddef;
+
+vardef DCL[] (text PRM) (expr lilb, rilb, ldlb, rdlb)
+  (suffix j_sty, a_sty, i_sty) text SUB=
+    NFR[@] (PRM) (lilb, rilb, ldlb, rdlb, j_sty, a_sty, i_sty);
+    jgm[@] SUB;
+enddef;
+
+vardef MVD[] (expr inf_num, lplb, rplb) (suffix a_sty, p_sty)=
+  if inf_num<1:
+    drv_errhelp "The minimal value is 1.";
+    drv_errmessage (decimal inf_num)&" is not a valid number of inference"&
+      " steps";
+  else:
+    save aux_idx, aux_sty, phm_jdg;
+    numeric aux_idx, aux_sty;
+    picture phm_jdg;
+    aux_sty:=check_path_style (p_sty, drv_phm_sty);
+    phm_jdg:=nullpicture;
+    setbounds phm_jdg to (0, 0)--(iln_hg[aux_sty]-iln_dp[aux_sty], 0)--cycle;
+    aux_idx:=@;
+    for i=1 upto inf_num:
+      phm_idx:=phm_idx-1;
+      box_init jdg[phm_idx] (phm_jdg);
+      sbj_num[phm_idx]:=0;
+      NFR[phm_idx] (aux_idx) ("", "", "", "", 0, a_sty, 0);
+      aux_idx:=phm_idx;
+    endfor
+    src[@]:=phm_idx;
+    tgt[phm_idx]:=@;
+    phm_sty[phm_idx]:=aux_sty;
+    %
+    % lplb, rplb: phantom steps labels
+    %
+    opt_init[plb_sty[drv_sty]] l_plb[phm_idx] lplb;
+    opt_init[plb_sty[drv_sty]] r_plb[phm_idx] rplb;
+    phm_idx
+  fi
+enddef;
+
+vardef bxd[]=
+  boxed[@]:=true;
+  @
+enddef;
+
+%
+% Optional labels & shorthands
+%
+
+numeric drv_jct_sty;	% default junction style
+string  drv_alg_sty;	% default junction style
+numeric drv_iln_sty;	% default inference line path-style
+numeric drv_phm_sty;	% default phantom steps path-style
+
+boolean drv_left_ilb;	% inference labels on the left
+boolean drv_left_dlb;	% delimiter labels (hence delimiters) on the left
+boolean drv_left_plb;	% phantom steps labels on the left
+
+vardef arg_type expr arg=
+  if picture arg:
+    "picture"
+  else:
+    "string"
+  fi
+enddef;
+
+vardef opt_lbls @# (text LBL) expr left_lbls=
+  save lbl_num, fst_lbl, snd_lbl;
+  numeric lbl_num;
+  lbl_num:=0;
+  for lbl=LBL:
+    if lbl_num=0:
+      scantokens (arg_type lbl) fst_lbl;
+      fst_lbl:=lbl;
+    elseif lbl_num=1:
+      scantokens (arg_type lbl) snd_lbl;
+      snd_lbl:=lbl;
+    else:
+      drv_errhelp "At most two labels can be specified:"&
+        " a left one and a right one.";
+      drv_errmessage "more than two labels have been specified";
+    fi
+    lbl_num:=lbl_num+1;
+  endfor
+  if lbl_num=0:
+    string @#.l;
+    string @#.r;
+    @#.l:="";
+    @#.r:="";
+  elseif lbl_num=1:
+    if left_lbls:
+      scantokens (arg_type fst_lbl) @#.l;
+      string @#.r;
+      @#.l:=fst_lbl;
+      @#.r:="";
+    else:
+      string @#.l;
+      scantokens (arg_type fst_lbl) @#.r;
+      @#.l:="";
+      @#.r:=fst_lbl;
+    fi
+  else:
+    scantokens (arg_type fst_lbl) @#.l;
+    scantokens (arg_type snd_lbl) @#.r;
+    @#.l:=fst_lbl;
+    @#.r:=snd_lbl;
+  fi
+enddef;
+
+vardef NFR_opt[] (text PRM) (text ILB) (text DLB)
+  (suffix j_sty, a_sty, i_sty)=
+    opt_lbls ilb (ILB) drv_left_ilb;
+    opt_lbls dlb (DLB) drv_left_dlb;
+    NFR[@] (PRM) (ilb.l, ilb.r, dlb.l, dlb.r, j_sty, a_sty, i_sty);
+enddef;
+
+vardef DCL_opt[] (text PRM) (text ILB) (text DLB)
+  (suffix j_sty, a_sty, i_sty) text SUB=
+    NFR_opt[@] (PRM) (ILB) (DLB) (j_sty, a_sty, i_sty);
+    jgm[@] SUB;
+enddef;
+
+vardef MVD_opt[] (expr inf_num) (text PLB) (suffix a_sty, p_sty)=
+  opt_lbls plb (PLB) drv_left_plb;
+  MVD[@] (inf_num, plb.l, plb.r, a_sty, p_sty)
+enddef;
+
+% Nfr, Dcl & Mvd
+
+vardef Nfr[] (text PRM) (expr ilb, ldlb, rdlb) (suffix i_sty)=
+  NFR_opt[@] (PRM) (ilb) (ldlb, rdlb) (_, _, i_sty);
+enddef;
+
+vardef Dcl[] (text PRM) (expr ilb, ldlb, rdlb) (suffix i_sty) text SUB=
+  Nfr[@] (PRM) (ilb, ldlb, rdlb, i_sty);
+  jgm[@] SUB;
+enddef;
+
+vardef Mvd[] (expr inf_num, lplb, rplb) (suffix p_sty)=
+  MVD[@] (inf_num, lplb, rplb, _, p_sty)
+enddef;
+
+% nfr, dcl & mvd
+
+vardef nfr[] (text PRM) (expr ilb) (suffix i_sty)=
+  NFR_opt[@] (PRM) (ilb) () (_, _, i_sty);
+enddef;
+
+vardef dcl[] (text PRM) (expr ilb) (suffix i_sty) text SUB=
+  nfr[@] (PRM) (ilb, i_sty);
+  jgm[@] SUB;
+enddef;
+
+vardef mvd[] (expr inf_num) (suffix p_sty)=
+  MVD_opt[@] (inf_num) () (_, p_sty)
+enddef;
+
+
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+%
+% Pictured paths
+%
+
+vardef dotted_aux (expr pth, dot_wd, dots_dist)=
+  save pth_len, pct;
+  numeric pth_len;
+  picture pct;
+  pth_len:=arclength pth;
+  pct:=nullpicture;
+  if dots_dist>0:
+    stp_num:=round ((pth_len-dot_wd)/dots_dist);
+    if stp_num>0:
+      stp_len:=(pth_len-dot_wd)/stp_num;
+      addto pct doublepath pth dashed dashpattern (on 0 off stp_len)
+        shifted (dot_wd/2, 0) withpen pencircle scaled dot_wd;
+    fi
+  fi
+  pct
+enddef;
+
+primarydef pth dotted wd_dist=
+  dotted_aux(pth, xpart wd_dist, ypart wd_dist)
+enddef;
+
+vardef expanded_aux (expr pth, scl, dir, stp_len)=
+  save pth_len, aux_len;
+  numeric pth_len, aux_len;
+  pth_len:=arclength pth;
+  if (stp_len>0) and (pth_len>stp_len):
+    aux_len:=pth_len/(pth_len div stp_len);
+    point arctime 0 of pth of pth shifted
+      (unitvector direction arctime 0 of pth of pth
+        rotated dir scaled scl)..
+          {direction arctime 0 of pth of pth}
+    for i=aux_len step aux_len until pth_len-aux_len:
+      point arctime i of pth of pth shifted
+        (unitvector direction arctime i of pth of pth
+          rotated dir scaled scl)
+            {direction arctime i of pth of pth}..
+    endfor
+    point arctime pth_len of pth of pth shifted
+      (unitvector direction arctime pth_len of pth of pth
+        rotated dir scaled scl)
+          {direction arctime pth_len of pth of pth}
+  else:
+    pth
+  fi
+enddef;
+
+primarydef pth expanded scl_dir_len=
+  expanded_aux (pth,
+    redpart scl_dir_len, greenpart scl_dir_len, bluepart scl_dir_len)
+enddef;
+
+vardef waved_aux (expr pth, amp)=
+  save pth_len, mid;
+  numeric pth_len, mid;
+  pth_len:=arclength pth;
+  if (amp>0) and (pth_len>2(1+sqrt 5)*amp):
+    mid:=pth_len/(2(pth_len div (2(1+sqrt 5)*amp)));
+    point arctime 0 of pth of pth shifted
+      (unitvector direction arctime 0 of pth of pth
+        rotated -90 scaled amp)
+          {direction arctime 0 of pth of pth}
+    for i=mid step 2mid until pth_len:
+    ..point arctime i of pth of pth shifted
+        (unitvector direction arctime i of pth of pth
+          rotated 90 scaled amp)
+            {direction arctime i of pth of pth}
+    ..point arctime i+mid of pth of pth shifted
+        (unitvector direction arctime i+mid of pth of pth
+          rotated -90 scaled amp)
+            {direction arctime i+mid of pth of pth}
+    endfor
+  else:
+    pth
+  fi
+enddef;
+
+primarydef pth waved amp=
+  waved_aux(pth, amp)
+enddef;
+
+vardef drv_styled_aux[] expr pth=
+  save sty_idx, pth_len, pct;
+  numeric sty_idx, pth_len;
+  picture pct;
+  sty_idx:=check_path_style (@, 1);
+  pth_len:=arclength pth;
+  pct:=nullpicture;
+  if sty_idx=1:
+    interim linecap:=butt;
+    addto pct doublepath pth withpen drv_pen;
+  elseif sty_idx=2:
+    interim linecap:=butt;
+    addto pct doublepath pth
+      expanded (1.25rul_thk[drv_sty],  90, rul_thk[drv_sty])
+      withpen drv_pen;
+    addto pct doublepath pth
+      expanded (1.25rul_thk[drv_sty], -90, rul_thk[drv_sty])
+      withpen drv_pen;
+  elseif sty_idx=3:
+    addto pct also pth dotted (rul_thk[drv_sty], 2rul_thk[drv_sty]);
+  elseif sty_idx=4:
+    if rul_thk[drv_sty]>0:
+      interim linecap:=butt;
+      save dsh_num, dsh_len;
+      numeric dsh_num, dsh_len;
+      dsh_num:=round(pth_len/(3rul_thk[drv_sty]));
+      dsh_len:=
+        if odd dsh_num:
+          pth_len/dsh_num
+        else:
+          pth_len/(dsh_num+1)
+        fi;
+      addto pct doublepath pth dashed dashpattern(on dsh_len off dsh_len)
+        withpen drv_pen;
+    fi
+  elseif sty_idx=5:
+    interim linecap:=butt;
+    addto pct doublepath pth
+      waved 1.25rul_thk[drv_sty] withpen drv_pen;
+  elseif (sty_idx=6) and (pth_len>0):
+    addto pct also pth dotted (pdt_hg[drv_sty], pdt_wd[drv_sty]);
+  fi
+  pct
+enddef;
+
+primarydef pth drv_styled sty=
+  drv_styled_aux[sty] pth
+enddef;
+
+
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+%
+% Delimiters
+%
+
+%
+% 1. Global parameters
+%
+
+string drv_l_dlm; % left delimiter LaTeX code
+string drv_r_dlm; % right delimiter LaTeX code
+
+%
+% 2. Macros
+%
+
+vardef minmax_y[]=(
+  if drv_bot_roots:
+    if known ccl[@]:
+      ypart jdg[@].c-num_hg+iln_hg[(iln_sty[ccl[@]])]
+        +min_clr_scl*min_clr[drv_sty]/2
+    else:
+      smin_y[@]-min_clr_scl*min_clr[drv_sty]
+    fi,
+    smax_y[@]+min_clr_scl*min_clr[drv_sty]
+  else:
+    smin_y[@]-min_clr_scl*min_clr[drv_sty],
+    if known ccl[@]:
+      ypart jdg[@].c-den_dp-iln_hg[(iln_sty[ccl[@]])]
+        -min_clr_scl*min_clr[drv_sty]/2
+    else:
+      smax_y[@]+min_clr_scl*min_clr[drv_sty]
+    fi
+  fi)
+enddef;
+
+vardef delim @# expr dlm_len=
+  save rule_str, dlm_str, dlm_pct, dlm_dp;
+  string rule_str, dlm_str;
+  picture dlm_pct;
+  numeric dlm_dp;
+  rule_str:="\rule{0bp}{"&(decimal(dlm_len/2+axis_hg[drv_sty]))&"bp}";
+  dlm_str:=
+    if str @#="l":
+      "\left"&drv_l_dlm&rule_str&"\right."
+    else:
+      "\left."&rule_str&"\right"&drv_r_dlm
+    fi;
+  dlm_pct:=mth_tex[drv_sty] dlm_str;
+  dlm_dp:=depth dlm_pct;
+  if dlm_dp=0:
+    nullpicture
+  else:
+    begingroup
+      setbounds dlm_pct to
+        (xpart llcorner dlm_pct,  dlm_dp)
+      --(xpart ulcorner dlm_pct, -dlm_dp)
+      --(xpart urcorner dlm_pct, -dlm_dp)
+      --(xpart lrcorner dlm_pct,  dlm_dp)
+      --cycle;
+      dlm_pct yscaled (dlm_len/(2*height dlm_pct))
+    endgroup
+  fi
+enddef;
+
+
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+%
+% Checking, building, freezing (very inefficient, to be improved)
+%
+
+%
+% 1. Global parameters
+%
+
+numeric min_clr_scl;		%
+numeric prm_skp_scl;		%
+numeric jdg_skp_scl;		%
+numeric ilb_skp_scl;		%
+numeric plb_skp_scl;		%
+
+boolean drv_bot_roots;		%
+boolean drv_boxmode_on;		%
+boolean drv_fractionmode_on;	%
+string  drv_axis_ref;		%
+
+%
+% 2. Macros
+%
+
+%
+% Checking
+%
+
+vardef fraction_inference[]=
+      (prm_num[@]=0)
+  and (iln_sty[@]=0)
+  and (unknown l_ilb[@])
+  and (unknown r_ilb[@])
+  and drv_fractionmode_on
+enddef;
+
+vardef drv_check_root[]=
+  if unknown jdg[@]:
+    drv_errhelp "An index must be used to declare a both a judgment and an"&
+      " inference.";
+    drv_errmessage (decimal @)&" has been used as an inference index but not"&
+      " as a judgment index";
+  elseif unknown prm_num[@]:
+    drv_errhelp "An index must be used to declare a both a judgment and an"&
+      " inference.";
+    drv_errmessage (decimal @)&" has been used as a judgment index but not"&
+      " as an inference index";
+  else:
+    save i_sty, prm_idx;
+    numeric i_sty, prm_idx;
+    i_sty:=iln_sty[@];
+    for prm_rnk=0 upto prm_num[@]-1:
+      prm_idx:=prm[@][prm_rnk];
+      drv_check_root[prm_idx];
+      %
+      % numerators and denominators clearances
+      % The TEXbook, Appendix G, Rule 15d.
+      %
+      if drv_bot_roots:
+        num_hg:=max(num_hg,
+          iln_hg[i_sty]+min_clr_scl*min_clr[drv_sty]-jdg[prm_idx].dp);
+      else:
+        den_dp:=min(den_dp,
+          iln_dp[i_sty]-min_clr_scl*min_clr[drv_sty]-jdg[prm_idx].hg);
+      fi
+    endfor
+    if not fraction_inference[@]:
+      if drv_bot_roots:
+        den_dp:=min(den_dp,
+          iln_dp[i_sty]-min_clr_scl*min_clr[drv_sty]-jdg[@].hg);
+      else:
+        num_hg:=max(num_hg,
+          iln_hg[i_sty]+min_clr_scl*min_clr[drv_sty]-jdg[@].dp);
+      fi
+    fi
+    if unknown boxed[@]:
+      boxed[@]:=false;
+    fi
+  fi
+enddef;
+
+vardef drv_check=
+  if root_num=0:
+    drv_errhelp "Well ...";
+    drv_errmessage "no inference has been declared";
+  else:
+    save root_idx;
+    numeric root_idx;
+    root_idx:=root[0];
+    drv_check_root[root_idx];
+    if root_num>1:
+      save root_str;
+      string root_str;
+      root_str:=decimal root_idx;
+      for idx=1 upto root_num-1:
+        root_idx:=root[idx];
+        drv_check_root[root_idx];
+        root_str:=root_str&", "&(decimal root_idx);
+      endfor
+      drv_message "warning, multiple root indices ("&root_str&").";
+    fi
+  fi
+  drv_checked:=true;
+enddef;
+
+%
+% Building
+%
+
+vardef drv_build_root[]=
+  %
+  % premises junction (from left to right)
+  %
+  for prm_rnk=0 upto  prm_num[@]-1:
+    drv_build_root[prm[@][prm_rnk]];
+    if prm_rnk>0:
+      save ll_idx, lr_idx, rl_idx, rr_idx;
+      save lmax_x, rmin_x, min_skp;
+      numeric ll_idx, lr_idx, rl_idx, rr_idx;
+      numeric lmax_x, rmin_x, min_skp;
+      ypart jdg[prm[@][prm_rnk-1]].c=ypart jdg[prm[@][prm_rnk]].c;
+      ll_idx:=prm[@][0];
+      lr_idx:=prm[@][prm_rnk-1];
+      rl_idx:=prm[@][prm_rnk];
+      rr_idx:=prm[@][prm_rnk];
+      lmax_x:=imax_x[lr_idx];
+      rmin_x:=imin_x[rl_idx];
+      min_skp[0]:=rmin_x-lmax_x;
+      forever:
+        exitif (unknown r_prm[lr_idx]) or (unknown l_prm[rl_idx]);
+        ll_idx:=l_prm[ll_idx];
+        lr_idx:=r_prm[lr_idx];
+        rl_idx:=l_prm[rl_idx];
+        rr_idx:=r_prm[rr_idx];
+        lmax_x:=max(lmax_x, imax_x[lr_idx]);
+        rmin_x:=min(rmin_x, imin_x[rl_idx]);
+        min_skp[0]:=min(min_skp[0], imin_x[rl_idx]-imax_x[lr_idx]);
+      endfor
+      min_skp[1]:=rmin_x-lmax_x;
+      if known r_prm[lr_idx]:
+        r_prm[rr_idx]:= r_prm[lr_idx];
+        lmax_x:=smax_x[lr_idx];
+      elseif known l_prm[rl_idx]:
+        l_prm[ll_idx]:=l_prm[rl_idx];
+        rmin_x:=smin_x[rl_idx];
+      fi
+      min_skp[2]:=rmin_x-lmax_x;
+      if jct_sty[@]<3:
+        min_skp[jct_sty[@]]=prm_skp_scl*prm_skp[drv_sty];
+      fi
+    fi
+  endfor
+  if  prm_num[@]>0:
+    l_prm[@]:=prm[@][0];
+    r_prm[@]:=prm[@][prm_num[@]-1];
+  fi
+  %
+  % judgment alignment
+  %
+  if prm_num[@]=0:
+    imin_x[@]:=xpart jdg[@].l-jdg_skp_scl*jdg_skp[jdg_sty[drv_sty]];
+    imax_x[@]:=xpart jdg[@].r+jdg_skp_scl*jdg_skp[jdg_sty[drv_sty]];
+  else:
+    save l_xref, r_xref;
+    l_xref=
+      if boxed[prm[@][0]]:
+        smin_x[prm[@][0]]
+      else:
+        xpart jdg[prm[@][0]].l
+      fi;
+    r_xref=
+      if boxed[prm[@][prm_num[@]-1]]:
+        smax_x[prm[@][prm_num[@]-1]]
+      else:
+        xpart jdg[prm[@][prm_num[@]-1]].r
+      fi;
+    if alg_sty[@]="l":
+      xpart jdg[@].l=l_xref;
+    elseif alg_sty[@]="c":
+      xpart jdg[@].c=(l_xref+r_xref)/2;
+    elseif alg_sty[@]="r":
+      xpart jdg[@].r=r_xref;
+    fi
+    imin_x[@]:=min(xpart jdg[@].l, l_xref)
+          -jdg_skp_scl*jdg_skp[jdg_sty[drv_sty]];
+    imax_x[@]:=max(xpart jdg[@].r, r_xref)
+          +jdg_skp_scl*jdg_skp[jdg_sty[drv_sty]];
+  fi
+  %
+  % inference line
+  %
+  save iln_wd, iln_pct;
+  numeric iln_wd;
+  picture iln_pct;
+  iln_wd:=imax_x[@]-imin_x[@];
+  iln_pct:=((0, 0)--(iln_wd, 0)) drv_styled iln_sty[@];
+  setbounds iln_pct to
+    (0, ypart llcorner iln_pct)
+  --(0, ypart ulcorner iln_pct)
+  --(iln_wd, ypart ulcorner iln_pct)
+  --(iln_wd, ypart llcorner iln_pct)
+  --cycle; % ! `linecap:=butt' and `linecap:=squared' -> same bounding box !
+  box_init iln[@] (iln_pct);
+  xpart iln[@].c=(imin_x[@]+imax_x[@])/2;
+  %
+  % orientation, smin_y & smax_y
+  %
+  if drv_bot_roots:
+    ypart iln[@].c=ypart jdg[@].c-den_dp;
+    smin_y[@]:=ypart jdg[@].c+jdg[@].dp;
+    smax_y[@]:=
+      if iln_sty[@]=0:
+        ypart jdg[@].c+jdg[@].hg
+      else:
+        ypart iln[@].c+iln[@].hg
+      fi;
+    if prm_num[@]>0:
+      ypart iln[@].c=ypart jdg[prm[@][0]].c-num_hg;
+      for prm_rnk=0 upto prm_num[@]-1:
+        smax_y[@]:=max(smax_y[@], smax_y[prm[@][prm_rnk]]);
+      endfor;
+    fi
+  else:
+    ypart iln[@].c=ypart jdg[@].c-num_hg;
+    smin_y[@]:=
+      if iln_sty[@]=0:
+        ypart jdg[@].c+jdg[@].dp
+      else:
+        ypart iln[@].c+iln[@].dp
+      fi;
+    smax_y[@]:=ypart jdg[@].c+jdg[@].hg;
+    if prm_num[@]>0:
+      ypart iln[@].c=ypart jdg[prm[@][0]].c-den_dp;
+      for prm_rnk=0 upto prm_num[@]-1:
+        smin_y[@]:=min(smin_y[@], smin_y[prm[@][prm_rnk]]);
+      endfor;
+    fi
+  fi
+  %
+  % inference labels
+  %
+  if known l_ilb[@]:
+    l_ilb[@].r=iln[@].l shifted (-ilb_skp_scl*ilb_skp[drv_sty], 0);
+    imin_x[@]:=xpart l_ilb[@].l;
+    smin_y[@]:=min(smin_y[@], ypart l_ilb[@].c+l_ilb[@].dp);
+    smax_y[@]:=max(smax_y[@], ypart l_ilb[@].c+l_ilb[@].hg);
+  fi
+  if known r_ilb[@]:
+    r_ilb[@].l=iln[@].r shifted (ilb_skp_scl*ilb_skp[drv_sty], 0);
+    imax_x[@]:=xpart r_ilb[@].r;
+    smin_y[@]:=min(smin_y[@], ypart r_ilb[@].c+r_ilb[@].dp);
+    smax_y[@]:=max(smax_y[@], ypart r_ilb[@].c+r_ilb[@].hg);
+  fi
+  %
+  % phantom steps
+  %
+  if known tgt[@]:
+    save phm_pth, phm_pct;
+    path phm_pth;
+    picture phm_pct;
+    save top_y, mid_y, bot_y;
+    numeric top_y, bot_y;
+    if drv_bot_roots:
+      bot_y:=xpart minmax_y[@]+min_clr_scl*min_clr[drv_sty]/2;
+      top_y:=xpart minmax_y[tgt[@]];
+    else:
+      bot_y:=ypart minmax_y[tgt[@]];
+      top_y:=ypart minmax_y[@]-min_clr_scl*min_clr[drv_sty]/2;
+    fi
+    mid_y:=(top_y+bot_y)/2;
+    phm_pth:=(0, (bot_y-top_y)/2)--(0, (top_y-bot_y)/2);
+    phm_pct:=phm_pth drv_styled phm_sty[@];
+    box_init phm[@] (phm_pct shifted ((width phm_pct)/2, 0));
+    phm[@].c=(xpart jdg[@].c, mid_y);
+    imin_x[@]:=min(imin_x[@], xpart phm[@].l);
+    imax_x[@]:=max(imax_x[@], xpart phm[@].r);
+    %
+    % phantom steps labels
+    %
+    if known l_plb[@]:
+      l_plb[@].r=phm[@].l shifted (-plb_skp[drv_sty], 0);
+      imin_x[@]:=min(imin_x[@], xpart l_plb[@].l);
+    fi
+    if known r_plb[@]:
+      r_plb[@].l=phm[@].r shifted ( plb_skp[drv_sty], 0);
+      imax_x[@]:=max(imax_x[@], xpart r_plb[@].r);
+    fi
+  fi
+  %
+  % smin_x & smax_x
+  %
+  smin_x[@]:=imin_x[@];
+  smax_x[@]:=imax_x[@];
+  for prm_rnk=0 upto prm_num[@]-1:
+    smin_x[@]:=min(smin_x[@], smin_x[prm[@][prm_rnk]]);
+    smax_x[@]:=max(smax_x[@], smax_x[prm[@][prm_rnk]]);
+  endfor
+  %
+  % delimiters
+  %
+  if known l_dlb[@] or known r_dlb[@]:
+    save idx, mmy, min_y, max_y;
+    numeric idx, min_y, max_y;
+    pair mmy;
+    mmy:=minmax_y[@];
+    min_y:=xpart mmy;
+    max_y:=ypart mmy;
+    if known l_dlb[@]:
+      box_init l_dlm[@] (delim l (max_y-min_y));
+      l_dlm[@].r=(smin_x[@], (max_y+min_y)/2);
+      l_dlb[@].r=l_dlm[@].l;
+      smin_x[@]:=xpart l_dlb[@].l;
+    fi
+    if known r_dlb[@]:
+      box_init r_dlm[@] (delim r (max_y-min_y));
+      r_dlm[@].l=(smax_x[@], (max_y+min_y)/2);
+      r_dlb[@].l=r_dlm[@].r;
+      smax_x[@]:=xpart r_dlb[@].r;
+    fi
+  fi
+  if (known l_dlb[@]) or boxed[@]:
+    idx:=@;
+    forever:
+      imin_x[idx]:=smin_x[@];
+      exitif unknown l_prm[idx];
+      idx:=l_prm[idx];
+    endfor
+  fi
+  if (known r_dlb[@]) or boxed[@]:
+    idx:=@;
+    forever:
+      imax_x[idx]:=smax_x[@];
+      exitif unknown r_prm[idx];
+      idx:=r_prm[idx];
+    endfor
+  fi
+enddef;
+
+vardef drv_build=
+  if not drv_checked:
+    drv_check;
+  fi
+  for idx=0 upto root_num-1:
+    drv_build_root[root[idx]];
+  endfor
+  drv_built:=true;
+enddef;
+
+%
+% Freezing
+%
+
+vardef drv_freeze_root[]=
+  for prm_rnk=0 upto prm_num[@]-1:
+    drv_freeze_root[prm[@][prm_rnk]];
+  endfor
+  for sbj_rnk=0 upto sbj_num[@]-1:
+    box_freeze sbj[@][sbj_rnk];
+  endfor
+  forsuffixes sfx=
+    iln, jdg, phm,
+    l_dlb, l_dlm, l_ilb, l_plb,
+    r_dlb, r_dlm, r_ilb, r_plb:
+      if known sfx[@]:
+        box_freeze sfx[@];
+      fi
+  endfor
+enddef;
+
+vardef drv_freeze=
+  if not drv_built:
+    drv_build;
+  fi
+  save root_idx;
+  numeric root_idx;
+  root_idx:=root[0];
+  if unknown iln[root_idx].c:
+    %
+    % default math axis
+    %
+    if drv_axis_ref="iln":
+      iln[root_idx].c=(0, axis_hg[drv_sty]);
+    else: % drv_axis_ref="jdg"
+      jdg[root_idx].c=(0, axis_hg[drv_sty]);
+    fi
+    drv_freeze_root[root_idx];
+  fi
+  for idx=1 upto root_num-1:
+    root_idx:=root[idx];
+    if unknown iln[root_idx].c:
+      smin_x[root_idx]=smax_x[root[idx-1]]+prm_skp_scl*prm_skp[drv_sty];
+      ypart iln[root_idx].c=ypart iln[root[idx-1]].c;
+    fi
+    drv_freeze_root[root_idx];
+  endfor
+  drv_frozen:=true;
+enddef;
+
+
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+%
+% Derivation tree pictures
+%
+
+%
+% 1. Global parameters
+%
+
+boolean drv_proofmode_on;	%
+color prf_clr;			%
+color jdg_clr;			%
+color sbj_clr;			%
+
+prf_clr:=.75background;		% arbitrary
+jdg_clr:=red;			% arbitrary
+sbj_clr:=blue;			% arbitrary
+
+%
+% 2. Macros
+%
+
+vardef drv_tree_addto @# (expr idx) text draw_options=
+  for prm_rnk=0 upto prm_num[idx]-1:
+    drv_tree_addto @# (prm[idx][prm_rnk]) draw_options;
+  endfor
+  forsuffixes sfx=
+    jdg, phm,
+    l_dlb, l_dlm, l_ilb, l_plb,
+    r_dlb, r_dlm, r_ilb, r_plb:
+      if known sfx[idx]:
+        addto @# also sfx[idx] draw_options;
+      fi
+  endfor
+  if iln_sty[idx]>0:
+      addto @# also iln[idx] draw_options;
+  fi
+enddef;
+
+vardef tt_nat[] expr nat= % typewriter typeface naturals
+  save nat_aux, nat_pct_wd, dgt_num, nat_pct;
+  numeric nat_aux, nat_pct_wd, dgt_num;
+  picture nat_pct;
+  nat_aux:=abs nat;
+  nat_pct:=nullpicture;
+  nat_pct_wd:=0;
+  dgt_num:=1;
+  forever:
+    exitif nat_aux div (10**dgt_num)=0;
+    dgt_num:=dgt_num+1;
+  endfor
+  for rnk:=1 upto dgt_num:
+    addto nat_pct also tt_dgt[@][nat_aux div (10**(dgt_num-rnk))]
+      shifted (nat_pct_wd, 0);
+    nat_pct_wd:=width nat_pct;
+    nat_aux:=nat_aux mod (10**(dgt_num-rnk));
+  endfor
+  nat_pct shifted (0, -axis_hg[@])
+enddef;
+
+vardef prf_tree_addto @# expr idx=
+  for prm_rnk=0 upto prm_num[idx]-1:
+    prf_tree_addto @# (prm[idx][prm_rnk]);
+  endfor
+  if idx>=0:
+    box_init jdg_prf[idx] (tt_nat[2] idx);
+    jdg_prf[idx].r=jdg[idx].l;
+    box_freeze jdg_prf[idx];
+    addto @# also jdg_prf[idx] withcolor jdg_clr;
+    addto @# doublepath jdg[idx].c withcolor jdg_clr
+      withpen pencircle scaled (2*pdt_hg[drv_sty]);
+  fi
+  for sbj_rnk=0 upto sbj_num[idx]-1:
+    box_init sbj_prf[idx][sbj_rnk] (tt_nat[3] sbj_rnk);
+    if odd sbj_rnk:
+      sbj_prf[idx][sbj_rnk].c shifted (0, sbj_prf[idx][sbj_rnk].hg)=
+        sbj[idx][sbj_rnk].c
+          shifted (0, -den_dp-min_clr_scl*min_clr[drv_sty]/2);
+    else:
+      sbj_prf[idx][sbj_rnk].c shifted (0, sbj_prf[idx][sbj_rnk].dp)=
+        sbj[idx][sbj_rnk].c
+          shifted (0, -num_hg+min_clr_scl*min_clr[drv_sty]/2);
+    fi
+    box_freeze sbj_prf[idx][sbj_rnk];
+    addto @# also sbj_prf[idx][sbj_rnk] withcolor sbj_clr;
+    addto @# doublepath sbj[idx][sbj_rnk].c withcolor sbj_clr
+      withpen pencircle scaled pdt_hg[drv_sty];
+  endfor
+enddef;
+
+vardef drv_tree=
+  save pct;
+  picture pct;
+  pct:=nullpicture;
+  if not drv_frozen:
+    drv_freeze;
+  fi
+  for root_idx=0 upto root_num-1:
+    if drv_proofmode_on:
+      drv_tree_addto pct (root[root_idx]) withcolor prf_clr;
+      prf_tree_addto pct (root[root_idx]);
+    else:
+      drv_tree_addto pct (root[root_idx]);
+    fi
+  endfor
+  pct
+enddef;
+
+vardef drv_bbox[]=
+  save min_x, max_x, mmy, min_y, max_y;
+  pair mmy;
+  numeric min_x, max_x, max_y, min_y;
+  if not drv_frozen:
+    drv_freeze;
+  fi
+  min_x:=
+    if known l_dlm[@].r:
+      xpart l_dlm[@].r
+    else:
+      smin_x[@]
+    fi-jdg_skp_scl*jdg_skp[jdg_sty[drv_sty]];
+  max_x:=
+    if known r_dlm[@].l:
+      xpart l_dlm[@].l
+    else:
+      smax_x[@]
+    fi+jdg_skp_scl*jdg_skp[jdg_sty[drv_sty]];
+  mmy:=minmax_y[@];
+  min_y:=xpart mmy;
+  max_y:=ypart mmy;
+  (min_x, min_y)--
+  (min_x, max_y)--
+  (max_x, max_y)--
+  (max_x, min_y)--
+  cycle
+enddef;
+
+vardef mth_axis @# (suffix ref_sfx) (expr idx)=
+  if not drv_frozen:
+    drv_freeze;
+  fi
+  if unknown prm_num[idx]:
+    drv_errhelp "An index must be used to declare an inference before it is"&
+      " used to set the math axis of a picture.";
+    drv_errmessage "no inference has been declared using index "&(decimal idx);
+  else:
+    save ref_str, yref;
+    string ref_str;
+    numeric yref;
+    ref_str:=str ref_sfx;
+    if ref_str="iln":
+      yref:=ypart iln[idx].c;
+    elseif ref_str="jdg":
+      yref:=ypart jdg[idx].c;
+    elseif ref_str="dlm":
+      if known l_dlm[idx]:
+        yref:=ypart l_dlm[idx].c;
+      elseif known r_dlm[idx]:
+        yref:=ypart r_dlm[idx].c;
+      else:
+        drv_errhelp "Well ...";
+        drv_errmessage "no delimiter is attached to inference "&(decimal idx);
+      fi
+    else:
+      drv_errhelp "Valid identifiers are"&
+        " iln (inference line axis),"&
+        " jdg (judgment math-axis) and"&
+        " dlm (delimiter axis).";
+      drv_errmessage (ref_str&" is not a valid reference type identifier");
+    fi
+    if known yref:
+      @#:=@# shifted (0, axis_hg[drv_sty]-yref);
+    fi
+  fi
+enddef;
+
+vardef drv_axis (suffix ref) (expr idx)=
+  mth_axis currentpicture (ref, idx);
+enddef;
+
+
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+%
+% Tunings
+%
+
+vardef check_math_style (expr sty_str, default)=
+  if sty_str="\displaystyle":
+    0
+  elseif sty_str="\textstyle":
+    1
+  elseif sty_str="\scriptstyle":
+    2
+  elseif sty_str="\scriptscriptstyle":
+    3
+  else:
+    begingroup
+      drv_errhelp "Valid commands are"&
+        " \displaystyle,"&
+        " \textstyle,"&
+        " \scriptstyle and"&
+        " \scriptscriptstyle.";
+      drv_errmessage (sty_str&" is not a valid math-style command");
+      default
+    endgroup
+  fi
+enddef;
+
+vardef check_position_left (suffix pos_sfx) (expr default)=
+  save pos_str;
+  string pos_str;
+  pos_str:=str pos_sfx;
+  if (pos_str="l"):
+    true
+  elseif (pos_str="r"):
+    false
+  else:
+    begingroup
+      drv_errhelp "Valid identifiers are l (left) and r (right).";
+      drv_errmessage (pos_str&" is not a valid label position identifier");
+      default
+    endgroup
+  fi
+enddef;
+
+vardef check_mode_on (suffix status_sfx) (expr default)=
+  save status_str;
+  string status_str;
+  status_str:=str status_sfx;
+  if status_str="on":
+    true
+  elseif status_str="off":
+    false
+  else:
+    begingroup
+      drv_errhelp "Possible identifiers are on and off";
+      drv_errmessage (status_str&" is not a valid status identifier");
+      default
+    endgroup
+  fi
+enddef;
+
+vardef drv_math_style (suffix typ_sfx) (expr sty_str)=
+  save typ_str, sty_idx;
+  string typ_str;
+  numeric sty_idx;
+  typ_str:=str typ_sfx;
+  if  (typ_str<>"drv")
+  and (typ_str<>"jdg")
+  and (typ_str<>"ilb")
+  and (typ_str<>"dlb")
+  and (typ_str<>"plb"):
+    drv_errhelp "Valid  identifiers are"&
+      " drv (derivation tree),"&
+      " jdg (judgment),"&
+      " ilb (inference label),"&
+      " dlb (delimiter label) and"&
+      " plb (phantom steps label).";
+    drv_errmessage (sty_str&" is not a valid component identifier");
+  else:
+    sty_idx:=check_math_style (sty_str, 0);
+    if typ_str="drv":
+      drv_sty:=sty_idx;
+    else:
+      forsuffixes sfx=scantokens (typ_str&"_sty"):
+        for idx=0 upto 3:
+          sfx[idx]:=min(idx+sty_idx, 3);
+        endfor
+      endfor
+    fi
+  fi
+enddef;
+
+vardef drv_scale (suffix scl_sfx) (expr scl)=
+  save scl_str;
+  string scl_str;
+  scl_str:=str scl_sfx;
+  if scl_str="clr":
+    min_clr_scl:=scl;
+  elseif scl_str="prm":
+    prm_skp_scl:=scl;
+  elseif (scl_str="jdg") or (scl_str="jgm"): % "jgm" is deprecated
+    jdg_skp_scl:=scl;
+  elseif (scl_str="ilb") or (scl_str="lbl"): % "lbl" is deprecated
+    ilb_skp_scl:=scl;
+  else:
+    drv_errhelp "Valid identifiers are"&
+      " clr,"&
+      " prm,"&
+      " jdg and"&
+      " ilb.";
+    drv_errmessage (scl_str&" is not a valid scale identifier");
+  fi
+enddef;
+
+vardef drv_junction_style suffix sty_sfx=
+  drv_jct_sty:=check_junction_style (sty_sfx, drv_jct_sty);
+enddef;
+
+vardef drv_alignment_style suffix sty_sfx=
+  drv_alg_sty:=check_alignment_style (sty_sfx, drv_alg_sty);
+enddef;
+
+vardef drv_path_style (suffix typ_sfx, sty_sfx)=
+  save typ_str;
+  string typ_str;
+  typ_str:=str typ_sfx;
+  if typ_str="iln":
+    drv_iln_sty:=check_path_style (sty_sfx, drv_iln_sty);
+  elseif typ_str="phm":
+    drv_phm_sty:=check_path_style (sty_sfx, drv_phm_sty);
+  else:
+    drv_errhelp "Valid identifiers are"&
+      " iln (inference line) and"&
+      " phm (phantom steps path).";
+    drv_errmessage (typ_str&" is not a valid path-type identifier");
+  fi
+enddef;
+
+vardef drv_labels_position_aux (suffix typ_sfx, pos_sfx)=
+  save typ_str, idt_str, pos_str;
+  string typ_str, idt_str, pos_str;
+  typ_str:=str typ_sfx;
+  if  typ_str="ilb":
+    drv_left_ilb:=check_position_left (pos_sfx, drv_left_ilb);
+  elseif typ_str="dlb":
+    drv_left_dlb:=check_position_left (pos_sfx, drv_left_dlb);
+  elseif typ_str="plb":
+    drv_left_plb:=check_position_left (pos_sfx, drv_left_plb);
+  else:
+    drv_errhelp "Valid identifiers are"&
+      " ilb (inference label),"&
+      " dlb (delimiter label) and"&
+      " plb (phantom steps label).";
+    drv_errmessage (typ_str&" is not a valid label-type identifier");
+  fi
+enddef;
+
+vardef drv_labels_position text ARG=
+  drv_labels_position_aux if pair ARG: ARG else: (ilb, ARG) fi;
+enddef;
+
+vardef drv_roots_position suffix pos_sfx=
+  save pos_str;
+  string pos_str;
+  pos_str:=str pos_sfx;
+  if pos_str="t":
+    drv_bot_roots:=false;
+  elseif pos_str="b":
+    drv_bot_roots:=true;
+  else:
+    drv_errhelp "Valid identifiers are"&
+      " t (top) and"&
+      " b (bottom).";
+    drv_errmessage (pos_str&" is not a valid root position identifier");
+  fi
+enddef;
+
+vardef drv_axis_reference suffix ref_sfx=
+  save ref_str;
+  string ref_str;
+  ref_str:=str ref_sfx;
+  if (ref_str<>"iln") and (ref_str<>"jdg"):
+    drv_errhelp "Valid identifiers are iln (inference line axis) and"&
+      " jdg (judgment math-axis).";
+    drv_errmessage (ref_str&" is not a valid reference identifier");
+  else:
+    drv_axis_ref:=ref_str;
+  fi
+enddef;
+
+vardef drv_delimiter (suffix pos_sfx) (expr dlm_str)=
+  if check_position_left (pos_sfx, true):
+    drv_l_dlm:=dlm_str;
+  else:
+    drv_r_dlm:=dlm_str;
+  fi
+enddef;
+
+vardef drv_left_delimiter expr dlm_str=
+  drv_delimiter (l, dlm_str);
+enddef;
+
+vardef drv_right_delimiter expr dlm_str=
+  drv_delimiter (r, dlm_str);
+enddef;
+
+vardef drv_box_mode suffix status_sfx=
+  drv_boxmode_on:=check_mode_on (status_sfx, drv_boxmode_on);
+enddef;
+
+vardef drv_fraction_mode suffix status_sfx=
+  drv_fractionmode_on:=check_mode_on (status_sfx, drv_fractionmode_on);
+enddef;
+
+vardef drv_proof_mode suffix status_sfx=
+  drv_proofmode_on:=check_mode_on (status_sfx, drv_proofmode_on);
+enddef;
+
+
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+%
+% Default settings
+%
+
+drv_font_size "\normalsize";
+drv_math_style (drv, "\displaystyle");
+drv_math_style (jdg, "\textstyle");
+drv_math_style (ilb, "\scriptstyle");
+drv_math_style (dlb, "\textstyle");
+drv_math_style (plb, "\textstyle");
+drv_scale (clr, 1);
+drv_scale (prm, 1);
+drv_scale (jdg, 1);
+drv_scale (ilb, 1);
+drv_junction_style 1;
+drv_alignment_style c;
+drv_path_style (iln, 1);
+drv_path_style (phm, 3);
+drv_labels_position (ilb, r);
+drv_labels_position (dlb, l);
+drv_labels_position (plb, l);
+drv_roots_position b;
+drv_axis_reference iln;
+drv_left_delimiter "\lbrace";
+drv_right_delimiter "\rbrace";
+drv_box_mode off;
+drv_fraction_mode on;
+drv_proof_mode off;
+
+
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+%
+% LaTeX inclusion macro
+%
+% \drv includes a picture file in such a way that the baseline of the included
+% picture coincides with the baseline of the inclusion point. The code for \drv
+% was suggested by Josselin Noirel on the fr.comp.text.tex usenet group.
+%
+% \usepackage{graphicx}
+% \makeatletter
+% \def\Gin@def@bp#1\relax#2#3{\gdef#2{#3}}
+% \newsavebox{\graphicsbox}
+% \newcommand*{\drv}[1]{%
+% \sbox{\graphicsbox}{\includegraphics{#1}}%
+% \raisebox{\Gin@lly bp}%
+% {\usebox{\graphicsbox}}}
+% \makeatother
diff --git a/Master/texmf-dist/doc/metapost/drv/sample/makefile b/Master/texmf-dist/doc/metapost/drv/sample/makefile
new file mode 100644
index 00000000000..ab57ffe9ace
--- /dev/null
+++ b/Master/texmf-dist/doc/metapost/drv/sample/makefile
@@ -0,0 +1,47 @@
+MAIN=			coq-sample
+
+$(MAIN).pdf:		$(MAIN).ps
+			ps2pdf $(MAIN).ps
+
+$(MAIN).ps:		$(MAIN).tex $(MAIN)-delayed.mp
+			latex $(MAIN)
+			dvips -t unknown $(MAIN) -o
+
+$(MAIN)-proof.pdf:	$(MAIN)-proof.ps
+			ps2pdf $(MAIN)-proof.ps
+
+$(MAIN)-proof.ps:	$(MAIN)-delayed.mp
+			latex $(MAIN)-proof
+			dvips -t unknown $(MAIN)-proof -o
+
+$(MAIN)-delayed.mp:	$(MAIN).mp
+			$(RM) $(MAIN)-delayed.mp
+			mpost $(MAIN)
+			mpost $(MAIN)
+
+.SILENT clean:
+			$(RM) drv.mpx
+			$(RM) $(MAIN).[0-9]*
+			$(RM) $(MAIN).aux
+			$(RM) $(MAIN).dvi
+			$(RM) $(MAIN).log
+			$(RM) $(MAIN).nav
+			$(RM) $(MAIN).out
+			$(RM) $(MAIN).snm
+			$(RM) $(MAIN).toc
+			$(RM) $(MAIN)-delayed.mp
+			$(RM) $(MAIN)-delayed.mpx
+			$(RM) $(MAIN)-proof.aux
+			$(RM) $(MAIN)-proof.dvi
+			$(RM) $(MAIN)-proof.log
+			$(RM) $(MAIN)-proof.nav
+			$(RM) $(MAIN)-proof.out
+			$(RM) $(MAIN)-proof.snm
+			$(RM) $(MAIN)-proof.tex
+			$(RM) $(MAIN)-proof.toc
+
+cleanall:		clean
+			$(RM) $(MAIN).pdf
+			$(RM) $(MAIN).ps
+			$(RM) $(MAIN)-proof.pdf
+			$(RM) $(MAIN)-proof.ps
diff --git a/Master/texmf-dist/doc/metapost/drv/sample/readme.txt b/Master/texmf-dist/doc/metapost/drv/sample/readme.txt
new file mode 100644
index 00000000000..b0c3c91b5e5
--- /dev/null
+++ b/Master/texmf-dist/doc/metapost/drv/sample/readme.txt
@@ -0,0 +1,14 @@
+# In order to compile the sources and to get a pdf file, use `make' or:
+
+# 1. run metapost TWICE:
+mpost coq-sample.mp
+mpost coq-sample.mp
+
+# 2. run latex (once):
+latex coq-sample.tex
+
+# 3. run dvips (once):
+dvips coq-sample.dvi -o
+
+# 4. run ps2pdf (once):
+ps2pdf coq-sample.ps
diff --git a/Master/texmf-dist/doc/metapost/drv/template/drv.mp b/Master/texmf-dist/doc/metapost/drv/template/drv.mp
new file mode 100644
index 00000000000..5eb38396144
--- /dev/null
+++ b/Master/texmf-dist/doc/metapost/drv/template/drv.mp
@@ -0,0 +1,2245 @@
+%% drv.mp 0.93
+%% Copyright 2009 Laurent M\'ehats
+%
+% This work may be distributed and/or modified under the
+% conditions of the LaTeX Project Public License, either version 1.3
+% of this license or (at your option) any later version.
+% The latest version of this license is in
+%   http://www.latex-project.org/lppl.txt
+% and version 1.3 or later is part of all distributions of LaTeX
+% version 2005/12/01 or later.
+%
+% This work has the LPPL maintenance status `maintained'.
+%
+% The Current Maintainer of this work is Laurent M\'ehats.
+% <laurent.mehats@gmail.com>
+%
+% This work consists of the file drv.mp
+
+
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+%
+% User's macros summary
+%
+%
+% * Judgment & inference declarations
+% ===================================
+%
+%   jgm <nat> <str list>
+%	<nat>		judgment index
+%	<str list>	sub-judgments math-mode LaTeX code
+%
+%   nfr <nat> (<nat list>) (<str>, <id>)
+%	<nat>		inference index
+%	<nat list>	list of premise indices
+%	<str>		inference label math-mode LaTeX code
+%	<id>		inference line style identifier
+%			(0, 1, 2, 3, 4, 5, 6 or _)
+%			  0	none
+%			  1	simple
+%			  2	double
+%			  3	dotted
+%			  4	dashed
+%			  5	waved
+%			  6	TeX-dotted
+%			  _	default (set by drv_path_style)
+%
+%   mvd <nat 1> (<nat 2>, <id>)
+%	<nat 1>		index of the origin judgment
+%	<nat 2>		number of phantom steps
+%	<id>		phantom steps path-style identifier
+%			(0, 1, 2, 3, 4, 5, 6 or _)
+%
+%   Nfr <nat> (<nat list>) (<str 1>, <str 2>, <str 3>, <id>)
+%	<nat>		inference index
+%	<nat list>	list of premise indices
+%	<str 1>		inference label math-mode LaTeX code
+%	<str 2>		left delimiter label math-mode LaTeX code
+%	<str 3>		right delimiter label math-mode LaTeX code
+%	<id>		inference line style identifier
+%			(0, 1, 2, 3, 4, 5, 6 or _)
+%
+%   Mvd <nat 1> (<nat 2>, <str 1>, <str 2>, <id>)
+%	<nat 1>		index of the origin judgment
+%	<nat 2>		number of phantom steps
+%	<str 1>		left label math-mode LaTeX code
+%	<str 2>		right label math-mode LaTeX code
+%	<id>		phantom steps path-style identifier
+%			(0, 1, 2, 3, 4, 5, 6 or _)
+%
+%   NFR <nat> (<nat list>) (<str 1>, <str 2>, <str 3>, <str 4>)
+%     (<id 1>, <id 2>, <id 3>)
+%	<nat>		inference index
+%	<nat list>	list of premise indices
+%	<str 1>		left inference label math-mode LaTeX code
+%	<str 2>		right inference label math-mode LaTeX code
+%	<str 3>		left delimiter label math-mode LaTeX code
+%	<str 4>		right delimiter label math-mode LaTeX code
+%	<id 1>		junction style identifier (0, 1, 2, 3 or _)
+%			  0	fully-interlacing
+%			  1	semi-interlacing
+%			  2	non-interlacing
+%			  3	user specified (tricky)
+%			  _	default (set by drv_junction_style)
+%	<id 2>		alignment style identifier (l, c, r, u or _)
+%			  l	left
+%			  c	centered
+%			  r	right
+%			  u	user specified (tricky)
+%			  _	default (set by drv_alignment_style)
+%	<id 3>		inference line style identifier
+%			(0, 1, 2, 3, 4, 5, 6 or _)
+%
+%   MVD <nat 1> (<nat 2>, <str 1>, <str 2>, <id 1> <id 2>)
+%	<nat 1>		index of the origin judgment
+%	<nat 2>		number of phantom steps
+%	<str 1>		left label math-mode LaTeX code
+%	<str 2>		right label math-mode LaTeX code
+%	<id 1>		alignment style identifier (l, c, r, u or _)
+%	<id 2>		phantom steps path-style identifier
+%			(0, 1, 2, 3, 4, 5, 6 or _)
+%
+%   NFR_opt <nat> (<nat list>) (<str list 1>) (<str list 2>)
+%     (<id 1>, <id 2>, <id 3>)
+%	<nat>		inference index
+%	<nat list>	list of premise indices
+%	<str list 1>	list of inference labels math-mode LaTeX code
+%	<str list 2>	list of delimiter labels math-mode LaTeX code
+%	<id 1>		junction style identifier (0, 1, 2, 3 or _)
+%	<id 2>		alignment style identifier (l, c, r, u or _)
+%	<id 3>		inference line style identifier
+%			(0, 1, 2, 3, 4, 5, 6 or _)
+%
+%   MVD_opt <nat 1> (<nat 2>) (<str list>) (<id 1> <id 2>)
+%	<nat 1>		index of the origin judgment
+%	<nat 2>		number of phantom steps
+%	<str list>	list of labels math-mode LaTeX code
+%	<id 1>		alignment style identifier (l, c, r or u)
+%	<id 2>		phantom steps path-style identifier
+%			(0, 1, 2, 3, 4, 5, 6 or _)
+%
+% * Tunings
+% =========
+%
+%   drv_font_size <str>
+%	<str>		LaTeX font-size command
+%			  "\tiny"
+%			  "\scriptsize"
+%			  "\footnotesize"
+%			  "\small"
+%			  "\normalsize"
+%			  "\large"
+%			  "\Large"
+%			  etc.
+%
+%   drv_math_style (<id>, <str>)
+%	<id>		component identifier (drv, jdg, ilb, dlb or plb)
+%			  drv	derivation trees
+%			  jdg	judgments
+%			  ilb	inference labels
+%			  dlb	delimiter labels
+%			  plb	phantom steps labels
+%	<str>		LaTeX math-style command
+%
+%   drv_scale (<id>, <float>)
+%	<id>		scale identifier (clr, prm, jdg or ilb)
+%			  clr	nice explanation soon (see examples)
+%			  prm	nice explanation soon (see examples)
+%			  jdg	nice explanation soon (see examples)
+%			  ilb	nice explanation soon (see examples)
+%	<float>		scale value
+%
+%   drv_junction_style <id>
+%	<id>		junction style identifier (0, 1 or 2)
+%			  0	``fully-interlacing''
+%			  1	``semi-interlacing''
+%			  2	``non-interlacing''
+%
+%   drv_alignment_style <id>
+%	<id>		alignment style identifier (l, c or r)
+%			  l	left
+%			  c	centered
+%			  r	right
+%
+%   drv_path_style (<id 1>, <id 2>)
+%	<id 1>		path-type identifier (iln or phm)
+%			  iln	inference lines
+%			  phm	phantom steps paths
+%	<id 2>		path-style identifier (0, 1, 2, 3, 4, 5 or 6)
+%
+%   drv_labels_position (<id 1>, <id 2>)
+%	<id 1>		label-type identifier (ilb, plb or dlb)
+%			  ilb	inference labels
+%			  dlb	delimiter labels
+%			  plb	phantom steps labels
+%	<id 2>		position identifier (l or r)
+%			  l	left
+%			  r	right
+%
+%   drv_roots_position <id>
+%	<id>		position identifier (t or b)
+%			  t	top
+%			  b	bottom
+%
+%   drv_axis_reference <id>
+%	<id>		reference identifier (iln or jdg)
+%			  iln	root inference line axis
+%			  jdg	root judgment math-axis
+%
+%   drv_left_delimiter <str>
+%	<str>		left delimiter math-mode LaTeX code
+%			  "("	$($
+%			  "["	$[$
+%			  "\lbrace"	$\lbrace$
+%			  "\langle"	$\langle$
+%			  etc.
+%
+%   drv_right_delimiter <str>
+%	<str>		right delimiter math-mode LaTeX code
+%			  ")"
+%			  "]"
+%			  "\rbrace"
+%			  "\rangle"
+%			  etc.
+%
+%   drv_box_mode <id>
+%	<id>		status identifier (on or off)
+%			  on
+%			  off
+%
+%   drv_fraction_mode <id>
+%	<id>		status identifier (on or off)
+%			  on
+%			  off
+%
+%   drv_proof_mode <id>
+%	<id>		status identifier (on or off)
+%			  on
+%			  off
+%
+% * Derivation tree pictures
+% ==========================
+%
+%   drv_bbox <nat>
+%	<nat>		sub-tree root index
+%
+%   drv_axis (<id>, <nat>)
+%	<id>		reference type identifier (iln, jdg or dlm)
+%			  iln	inference line axis
+%			  jdg	judgment math-axis
+%			  dlm	delimiter axis
+%	<nat>		reference index
+%
+%   <path> drv_styled <id>
+%	<path>		MetaPost path expression
+%	<id>		path style identifier (0, 1, 2, 3, 4, 5 or 6)
+%
+
+
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+%
+% MetaPost messages formatting
+%
+
+% drv_format prevents messages from being automatically cut into lines every
+% 79 characters: if possible, a word which would otherwise be cut is 'pushed'
+% to the following line by inserting space characters before it.
+
+vardef drv_format (expr str, fst_len, nxt_len, dbl_pcs)=
+  % str: the message to be formatted
+  % fst_len: first line length
+  % nxt_len: following lines length
+  % dbl_pcs (boolean): occurrences of the percent character must be doubled
+  save str_len, sub_len, aux_len, chr_rnk, occ_num;
+  numeric str_len, sub_len, aux_len, chr_rnk, occ_num;
+  save aux_str, chr;
+  string aux_str, chr;
+  str_len:=length str;
+  sub_len:=0;
+  chr_rnk:=0;
+  occ_num:=0;
+  aux_len:=0;
+  aux_str:="";
+  forever:
+    exitif (chr_rnk=fst_len) or (chr_rnk=str_len);
+    chr:=substring (chr_rnk, chr_rnk+1) of str;
+    aux_str:=aux_str&chr;
+    if chr=" ":
+      sub_len:=chr_rnk+1;
+      aux_len:=sub_len+occ_num;
+    elseif (chr="%") and dbl_pcs:
+      aux_str:=aux_str&"%";
+      occ_num:=occ_num+1;
+    fi
+    chr_rnk:=chr_rnk+1;
+  endfor
+  if chr_rnk=fst_len:
+    begingroup
+      if sub_len=0:
+        sub_len:=fst_len;
+        aux_len:=sub_len+occ_num;
+      fi
+      substring (0, aux_len) of aux_str&
+        for idx=sub_len+1 upto fst_len:
+          " "&
+        endfor
+        drv_format (substring (sub_len, str_len) of str,
+          nxt_len, nxt_len, dbl_pcs)
+    endgroup
+  else:
+    aux_str
+  fi
+enddef;
+
+boolean drv_inside_fig;
+drv_inside_fig:=false;
+
+vardef drv_context=
+  "drv"&if drv_inside_fig: " (fig. "&decimal charcode&")"&fi ": "
+enddef;
+
+vardef drv_message expr str=
+  message drv_format (drv_context&str, 79, 79, false);
+enddef;
+
+vardef drv_errhelp expr str=
+  % Occurrences of the percent character must be doubled: errhelp makes single
+  % single occurrences behave as newline characters (this is inherited from
+  % MetaFont).
+  errhelp drv_format (str, 79, 79, true);
+enddef;
+
+vardef drv_errmessage expr str=
+  % errmessage inserts the 2-characters string  "! " before its argument.
+  % Hence 77 as a first line length argument.
+  errmessage drv_format (drv_context&str, 77, 79, false);
+enddef;
+
+
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+%
+% Delayed LaTeX processing
+%
+
+picture tex_pct[];
+string delayed_tex_file;
+delayed_tex_file:=jobname&"-delayed.mp";
+
+%
+% reading LaTeX picture definitions
+%
+
+boolean drv_nullpicture;
+drv_nullpicture:=true;
+
+string readfrom_str;
+readfrom_str:=readfrom delayed_tex_file;
+if readfrom_str<>EOF:
+  closefrom delayed_tex_file;
+  drv_message ("reading `"&delayed_tex_file&"' LateX picture definitions.");
+  batchmode;
+  scantokens ("input "&delayed_tex_file);
+  errorstopmode;
+  drv_message "done.";
+  drv_nullpicture:=false;
+fi
+
+%
+% copying LaTeX preamble
+%
+
+vardef drv_read (expr search_str) (suffix accum_str)=
+  save readfrom_str, readfrom_substr;
+  string readfrom_str, readfrom_substr;
+  accum_str:="";
+  forever:
+    readfrom_str:=readfrom jobname;
+    readfrom_substr:=substring (0, length search_str) of readfrom_str;
+    exitif (readfrom_substr=search_str) or (readfrom_str=EOF);
+    accum_str:=accum_str&readfrom_str&char(10);
+  endfor
+  if readfrom_str=EOF:
+    closefrom jobname;
+    drv_errhelp ("`"&jobname&".mp' should contain a line starting with "&
+      ditto&search_str&ditto&".");
+    drv_errmessage (ditto&search_str&ditto&" is missing");
+  fi
+enddef;
+
+string tex_preamble_str[];
+% tex_preamble_str[0] from "verbatimtex %&latex" to "\begin{document}"
+% tex_preamble_str[1] from "\begin{document}" to "etex;"
+
+drv_message ("reading `"&jobname&".mp' LateX preamble.");
+  drv_read ("verbatimtex %&latex", tex_preamble_str[0]);
+  drv_read ("\begin{document}", tex_preamble_str[0]);
+  drv_read ("etex;", tex_preamble_str[1]);
+  closefrom jobname;
+  write
+    "%"&char(10)&
+    "% AUTOMATICALLY GENERATED BY DRV.MP - DO NOT MODIFY."&char(10)&
+    "%"&char(10)&char(10)&
+    "verbatimtex %&latex"&char(10)&
+    tex_preamble_str[0]&
+    "\begin{document}"&char(10)&
+    tex_preamble_str[1]&
+    "etex;"
+  to delayed_tex_file;
+drv_message "done.";
+
+%
+% writing LaTeX picture definitions
+%
+
+numeric tex_pct_idx;
+tex_pct_idx:=0;
+
+% Math style indices: 0, 1, 2, 3
+string mth_sty_str[];
+mth_sty_str[0]:="\displaystyle";
+mth_sty_str[1]:="\textstyle";
+mth_sty_str[2]:="\scriptstyle";
+mth_sty_str[3]:="\scriptscriptstyle";
+
+string drv_fontsize;
+
+vardef drv_tex[] expr tex_str=
+  % @: math style index
+  % tex_str: math mode LaTeX code
+  save def_str, pct;
+  string def_str;
+  picture pct;
+  def_str:="btex{"&drv_fontsize&"$"&mth_sty_str[@]&"{}"&tex_str&"{}$}etex;";
+  write "tex_pct["&(decimal tex_pct_idx)&"]:="&def_str to delayed_tex_file;
+  pct:=
+    if known tex_pct[tex_pct_idx]:
+      tex_pct[tex_pct_idx]
+    else:
+      nullpicture
+    fi;
+  tex_pct_idx:=tex_pct_idx+1;
+  pct
+enddef;
+
+
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+%
+% MetaPost shorthands
+%
+
+vardef depth expr pct=
+  ypart llcorner pct
+enddef;
+
+vardef height expr pct=
+  ypart urcorner pct
+enddef;
+
+vardef width expr pct=
+  xpart urcorner pct-xpart llcorner pct
+enddef;
+
+
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+%
+% Font-specific parameters
+%
+
+%
+% em[s]		width of an m (s: mathstyle index)
+% ex[s]		height of an x
+% axis_hg[s]	height of the mathematical axis
+% num_bl_hg[s]	height of a numerator baseline w.r.t. the fraction bar axis
+% den_bl_dp[s]	depth of a denominator baseline w.r.t. the fraction bar axis
+% rul_thk[s]	default rule thickness
+%
+
+numeric em[], ex[], axis_hg[], num_bl_hg[], den_bl_dp[], rul_thk[];
+
+%
+% thn_sp[s]	thin space, usually 1em/6
+% med_sp[s]	medium space, usually 2em/9
+% thk_sp[s]	thick space, usually 5em/18
+%
+
+numeric thn_sp[], med_sp[], thk_sp[];
+
+%
+% pdt_hg[s]	height of a punctuation ldot
+% pdt_wd[s]	width of a punctuation ldot
+%
+
+numeric pdt_hg[], pdt_wd[];
+
+%
+% tt_dgt[s][i]	typewriter typeface digits (i ranges from 0 to 9)
+%
+
+picture tt_dgt[][];
+
+%
+% min_clr[s]	minimal clearance between a numerator
+%		or a denominator and the fraction bar
+% prm_skp[s]	<nice explanation>
+% jdg_skp[s]	<nice explanation>
+% ilb_skp[s]	<nice explanation>
+% plb_skp[s]	<nice explanation>
+%
+
+numeric min_clr[], prm_skp[], jdg_skp[], ilb_skp[], plb_skp[];
+
+vardef drv_fontdimen[] expr font=
+  save dim_pct;
+  picture dim_pct;
+  dim_pct:=drv_tex[0] ("\rule{\the\fontdimen"&(decimal @)&font&"}{0bp}");
+  width dim_pct
+enddef;
+
+vardef drv_font_size expr size_str=
+  save pdt_pct, sp_pct;
+  picture pdt_pct, sp_pct;
+  drv_fontsize:=size_str;
+  write char(10)&"% font-specific parameters ("&drv_fontsize&")"&char(10)
+    to delayed_tex_file;
+  ex[0]:=drv_fontdimen[5] "\textfont2";
+  ex[1]:=drv_fontdimen[5] "\textfont2";
+  ex[2]:=drv_fontdimen[5] "\scriptfont2";
+  ex[3]:=drv_fontdimen[5] "\scriptscriptfont2";
+  em[0]:=drv_fontdimen[6] "\textfont2";
+  em[1]:=drv_fontdimen[6] "\textfont2";
+  em[2]:=drv_fontdimen[6] "\scriptfont2";
+  em[3]:=drv_fontdimen[6] "\scriptscriptfont2";
+  rul_thk[0]:=drv_fontdimen[8] "\textfont3";
+  rul_thk[1]:=drv_fontdimen[8] "\textfont3";
+  rul_thk[2]:=drv_fontdimen[8] "\scriptfont3";
+  rul_thk[3]:=drv_fontdimen[8] "\scriptscriptfont3";
+  axis_hg[0]:=drv_fontdimen[22] "\textfont2";
+  axis_hg[1]:=drv_fontdimen[22] "\textfont2";
+  axis_hg[2]:=drv_fontdimen[22] "\scriptfont2";
+  axis_hg[3]:=drv_fontdimen[22] "\scriptscriptfont2";
+  num_bl_hg[0]:=(drv_fontdimen[8] "\textfont2")-axis_hg[0];
+  num_bl_hg[1]:=(drv_fontdimen[9] "\textfont2")-axis_hg[1];
+  num_bl_hg[2]:=(drv_fontdimen[9] "\scriptfont2")-axis_hg[2];
+  num_bl_hg[3]:=(drv_fontdimen[9] "\scriptscriptfont2")-axis_hg[3];
+  den_bl_dp[0]:=-(drv_fontdimen[11] "\textfont2")-axis_hg[0];
+  den_bl_dp[1]:=-(drv_fontdimen[12] "\textfont2")-axis_hg[1];
+  den_bl_dp[2]:=-(drv_fontdimen[12] "\scriptfont2")-axis_hg[2];
+  den_bl_dp[3]:=-(drv_fontdimen[12] "\scriptscriptfont2")-axis_hg[3];
+  min_clr[0]:=3*rul_thk[0]; % The TEXbook,
+  min_clr[1]:=1*rul_thk[1]; % Appendix G,
+  min_clr[2]:=1*rul_thk[2]; % Rule 15d.
+  min_clr[3]:=1*rul_thk[3]; %
+  for mth_sty:=0 upto 3:
+    sp_pct:=drv_tex[mth_sty] "\,";
+    thn_sp[mth_sty]:=width sp_pct;
+    sp_pct:=drv_tex[mth_sty] "\>";
+    med_sp[mth_sty]:=width sp_pct;
+    sp_pct:=drv_tex[mth_sty] "\;";
+    thk_sp[mth_sty]:=width sp_pct;
+    pdt_pct:=drv_tex[mth_sty] "\ldotp";
+    pdt_hg[mth_sty]:=height pdt_pct;
+    pdt_wd[mth_sty]:=width pdt_pct;
+    for dgt=0 upto 9:
+      tt_dgt[mth_sty][dgt]:=drv_tex[mth_sty] "\texttt{"&(decimal dgt)&"}";
+    endfor
+    prm_skp[mth_sty]:=3*med_sp[mth_sty]; % arbitrary
+    jdg_skp[mth_sty]:=thn_sp[mth_sty];   % arbitrary
+    ilb_skp[mth_sty]:=thn_sp[mth_sty];   % arbitrary
+    plb_skp[mth_sty]:=thk_sp[mth_sty];   % arbitrary
+  endfor
+enddef;
+
+
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+%
+% Math-related parameters & macros
+%
+
+%
+% Math styles
+% drv_sty		derivation trees
+% jdg_sty[drv_sty]	judgments
+% ilb_sty[drv_sty]	inference labels
+% dlb_sty[drv_sty]	delimiter labels
+% plb_sty[drv_sty]	phantom steps labels
+%
+
+numeric drv_sty, jdg_sty[], ilb_sty[], dlb_sty[], plb_sty[];
+
+%
+% Math-axis centered LaTeX pictures
+%
+
+vardef mth_tex[] expr tex_str=
+  (drv_tex[@] tex_str) shifted (0, -axis_hg[@])
+enddef;
+
+
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+%
+% drv-boxes
+%
+
+vardef drv_box text STR=
+  for str=STR:
+    expandafter picture scantokens str;
+    expandafter pair scantokens str.l;
+    expandafter pair scantokens str.c;
+    expandafter pair scantokens str.r;
+    expandafter numeric scantokens str.hg;
+    expandafter numeric scantokens str.dp;
+  endfor
+enddef;
+
+vardef box_init @# (expr pct)=
+  @#:=pct;
+  @#.r-@#.l=(width pct, 0);
+  @#.c=(@#.l+@#.r)/2;
+  @#.hg:=height pct;
+  @#.dp:=depth pct;
+enddef;
+
+vardef box_freeze @#=
+  @#:=@# shifted @#.l;
+enddef;
+
+
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+%
+% beginfig & endfig
+%
+
+%
+% drv_beginfig: figure initialization
+%
+
+pen drv_pen;
+
+vardef drv_beginfig=
+  %
+  % Judgments
+  %
+  % jdg[i]	judgment drv-box
+  % sbj_num[i]	number of sub-judgments
+  % sbj[i][j]	sub-judgment drv-box (j ranges from 0 to sbj_num[i]-1)
+  %
+  drv_box "jdg[]";
+  numeric sbj_num[];
+  drv_box "sbj[][]";
+  %
+  % Inferences
+  %
+  % prm_num[i]	number of premises
+  % prm[i][j]	premise index (j ranges from 0 to prm_num[i]-1)
+  % ccl[i]	conclusion index
+  % jct_sty[i]	junction style
+  % alg_sty[i]	alignment style
+  % iln_sty[i]	inference line style
+  % l_prm[i]	leftmost `graphical' premise index
+  % r_prm[i]	rightmost `graphical' premise index
+  %
+  numeric prm_num[], prm[][], ccl[];
+  numeric jct_sty[];
+  string alg_sty[];
+  numeric iln_sty[];
+  numeric l_prm[], r_prm[];
+  %
+  % imin_x[i]	inference minimal x
+  % l_dlb[i]	left delimiter label drv-box
+  % l_dlm[i]	left delimiter drv-box
+  % l_ilb[i]	left label drv-box
+  % iln[i]	inference line drv-box
+  % r_ilb[i]	right label drv-box
+  % r_dlm[i]	right delimiter drv-box
+  % r_dlb[i]	right delimiter label drv-box
+  % imax_x[i]	inference maximal x
+  %
+  numeric imin_x[];
+  drv_box "l_dlb[]", "l_dlm[]", "l_ilb[]";
+  drv_box "iln[]";
+  drv_box "r_ilb[]", "r_dlm[]", "r_dlb[]";
+  numeric imax_x[];
+  %
+  % Sub-trees
+  %
+  % smin_x[i]	sub-tree minimal x
+  % smax_x[i]	sub-tree maximal x
+  % smin_y[i]	sub-tree minimal y
+  % smax_y[i]	sub-tree maximal y
+  % boxed[i]	boolean
+  %
+  numeric smin_x[], smax_x[], smin_y[], smax_y[];
+  boolean boxed[];
+  %
+  % Pen initialization
+  %
+  drv_pen:=pencircle scaled rul_thk[drv_sty];
+  %
+  % num_hg	height of a numerator axis w.r.t. the fraction bar axis
+  % den_dp	depth of a denominator axis w.r.t. the fraction bar axis
+  % iln_hg[s]	height of a style s inference line
+  % iln_dp[s]	depth of a style s inference line
+  %
+  numeric num_hg, den_dp, iln_hg[], iln_dp[];
+  num_hg:=num_bl_hg[drv_sty]+axis_hg[jdg_sty[drv_sty]];
+  den_dp:=den_bl_dp[drv_sty]+axis_hg[jdg_sty[drv_sty]];
+  picture iln_pct;
+  for sty=0 upto 6:
+    iln_pct:=((0, 0)--(10, 0)) drv_styled sty;
+    iln_hg[sty]:=height iln_pct;
+    iln_dp[sty]:=depth iln_pct;
+  endfor
+  %
+  % Derivation trees
+  %
+  % root_num	number of roots
+  % root[i]	root index (i ranges from 0 to root_num-1)
+  % drv_built	boolean
+  % drv_frozen	boolean
+  %
+  numeric root_num, root[];
+  boolean drv_checked, drv_built, drv_frozen;
+  root_num:=0;
+  drv_checked:=false;
+  drv_built:=false;
+  drv_frozen:=false;
+  %
+  % Phantom steps
+  %
+  % phm_idx	phantom inferences index
+  % src[i]	base phantom judgment index (in case of an origin judgment)
+  % tgt[i]	origin judgment index (in case of a base phantom judgment)
+  % phm_sty[i]	phantom steps style
+  % l_plb[i]	left phantom steps label drv-box (in case of a base
+  %		phantom judgment)
+  % phm[i]	phantom steps drv-box (in case of a base phantom
+  %		judgment)
+  % r_plb[i]	right phantom steps label drv-box (in case of a base
+  %		phantom judgment)
+  %
+  numeric phm_idx, src[], tgt[], phm_sty[];
+  phm_idx:=0;
+  drv_box "l_plb[]", "phm[]", "r_plb[]";
+  %
+  % Proof pictures
+  %
+  % jdg_prf[i]		judgment index drv-box
+  % sbj_prf[i][j]	sub-judgment index drv-box (j ranges from 0 to
+  %			sbj_num[i]-1)
+  %
+  drv_box "jdg_prf[]", "sbj_prf[][]";
+  %
+  % Info
+  %
+  write char(10)&"% fig. "&(decimal charcode)&char(10) to delayed_tex_file;
+  drv_inside_fig:=true; % context: inside a figure
+enddef;
+
+extra_beginfig:=extra_beginfig&"drv_beginfig;";
+
+%
+% drv_endfig: proof-file generation
+%
+
+string proof_file;
+proof_file:=jobname&"-proof.tex";
+
+% TODO: taking outputtemplate into account.
+vardef output_file[]=
+  jobname&"."&(decimal @)
+enddef;
+
+string buf_str;
+buf_str:=
+  "%"&char(10)&
+  "% AUTOMATICALLY GENERATED BY DRV.MP."&char(10)&
+  "%"&char(10)&char(10)&
+  tex_preamble_str[0]&
+  "\usepackage{graphicx}"&char(10)&
+  "\makeatletter"&char(10)&
+  "\def\Gin@def@bp#1\relax#2#3{\gdef#2{#3}}"&char(10)&
+  "\newsavebox{\graphicsbox}"&char(10)&
+  "\newcommand*{\drv}[1]{%"&char(10)&
+  "\sbox{\graphicsbox}{\includegraphics{#1}}%"&char(10)&
+  "\raisebox{\Gin@lly bp}%"&char(10)&
+  "{\usebox{\graphicsbox}}}"&char(10)&
+  "\makeatother"&char(10)&char(10)&
+  "\newcount\h"&char(10)&
+  "\newcount\m"&char(10)&
+  "\h=\time"&char(10)&
+  "\divide\h 60"&char(10)&
+  "\m=-\h"&char(10)&
+  "\multiply\m 60"&char(10)&
+  "\advance\m\time"&char(10)&
+  "\def\hm{\number\h:\ifnum\m<10{}0\fi\number\m}"&char(10)&char(10)&
+  "\newcommand{\mathaxis}{\frac{\quad}{}}"&char(10)&char(10)&
+  "\begin{document}"&char(10)&
+  tex_preamble_str[1]&
+  "\noindent\today\ at \hm\medskip"&char(10)&char(10)&"\noindent";
+
+vardef drv_endfig=
+  drv_inside_fig:=false;   % context: outside a figure
+  buf_str:=buf_str&char(10)&
+  "\texttt{"&output_file[charcode]&"}"&char(10)&
+  "  (\verb+"&drv_fontsize&"+, \verb+"&(mth_sty_str[drv_sty])&"+)"&char(10)&
+  "    {"&drv_fontsize&char(10)&
+  "      \["&(mth_sty_str[drv_sty])&char(10)&
+  "        \mathaxis\drv{"&output_file[charcode]&"}\mathaxis"&char(10)&
+  "      \]}\\";
+  write EOF to proof_file; % erases the previous content
+  write buf_str&char(10)&"\end{document}" to proof_file;
+  write EOF to proof_file;
+  if drv_nullpicture:
+    draw btex{\tt drv}: run {\tt mpost} again.etex withcolor (1, 0, 0);
+  fi
+enddef;
+
+extra_endfig:="drv_endfig;"&extra_endfig;
+
+
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+%
+% Judgment declarations
+%
+
+vardef jgm[] text SUB=
+  % @: judgment index
+  % SUB: list of `sub-judgments' (pictures or strings)
+  if @<0:
+    drv_errhelp "An judgment index can not be negative.";
+    drv_errmessage (decimal @)&" is negative";
+  elseif known jdg[@]:
+    drv_errhelp "An index can be used only once to declare a judgment.";
+    drv_errmessage (decimal @)&" has been used already as a judgment index";
+  else:
+    save jdg_pct, sbj_pct, jdg_wd, sbj_rnk;
+    picture jdg_pct, sbj_pct;
+    numeric jdg_wd, sbj_rnk;
+    jdg_pct:=nullpicture;
+    jdg_wd:=0;
+    sbj_rnk:=0;
+    for sub=SUB:
+      sbj_pct:=
+        if picture sub:
+          sub
+        elseif sub<>"":
+          mth_tex[jdg_sty[drv_sty]] sub
+        else:
+          nullpicture
+        fi;
+      box_init sbj[@][sbj_rnk] (sbj_pct);
+      if sbj_rnk>0:
+        sbj[@][sbj_rnk-1].r=sbj[@][sbj_rnk].l;
+      fi
+      addto jdg_pct also sbj_pct shifted (jdg_wd, 0);
+      jdg_wd:=width jdg_pct;
+      sbj_rnk:=sbj_rnk+1;
+    endfor
+    sbj_num[@]:=sbj_rnk;
+    box_init jdg[@] (jdg_pct);
+    if sbj_num[@]>0:
+      jdg[@].l=sbj[@][0].l;
+      jdg[@].r=sbj[@][sbj_num[@]-1].r;
+    fi
+  fi
+enddef;
+
+
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+%
+% Inference declarations
+%
+
+vardef check_junction_style (suffix sty_sfx) (expr default)=
+  save sty_str;
+  string sty_str;
+  sty_str:=str sty_sfx;
+  if (sty_str="0")
+  or (sty_str="1")
+  or (sty_str="2")
+  or (sty_str="3"):
+    sty_sfx
+  elseif (sty_str="_"):
+    default
+  else:
+    begingroup
+      drv_errhelp "Valid identifiers are"&
+        " 0 (fully-interlacing),"&
+        " 1 (semi-interlacing),"&
+        " 2 (non-interlacing),"&
+        " 3 (user specified) and"&
+        " _ (default).";
+      drv_errmessage sty_str&" is not a valid junction style identifier";
+      default
+    endgroup
+  fi
+enddef;
+
+vardef check_alignment_style (suffix sty_sfx) (expr default)=
+  save sty_str;
+  string sty_str;
+  sty_str:=str sty_sfx;
+  if (sty_str="l")
+  or (sty_str="c")
+  or (sty_str="r")
+  or (sty_str="u"):
+    sty_str
+  elseif (sty_str="_"):
+    default
+  else:
+    begingroup
+      drv_errhelp "Valid identifiers are"&
+        " l (none),"&
+        " c (simple),"&
+        " r (double),"&
+        " u (dotted) and"&
+        " _ (default).";
+      drv_errmessage sty_str&" is not a valid alignment style identifier";
+      default
+    endgroup
+  fi
+enddef;
+
+vardef check_path_style (suffix sty_sfx) (expr default)=
+  save sty_str;
+  string sty_str;
+  sty_str:=str sty_sfx;
+  if (sty_str="0")
+  or (sty_str="1")
+  or (sty_str="2")
+  or (sty_str="3")
+  or (sty_str="4")
+  or (sty_str="5")
+  or (sty_str="6"):
+    sty_sfx
+  elseif (sty_str="_"):
+    default
+  else:
+    begingroup
+      drv_errhelp "Valid identifiers are"&
+        " 0 (none),"&
+        " 1 (simple),"&
+        " 2 (double),"&
+        " 3 (dotted),"&
+        " 4 (dashed),"&
+        " 5 (waved),"&
+        " 6 (TeX-dotted) and"&
+        " _ (default).";
+      drv_errmessage sty_str&" is not a valid path style identifier";
+      default
+    endgroup
+  fi
+enddef;
+
+vardef opt_init[] @# expr arg=
+  if picture arg:
+    if arg<>nullpicture:
+      box_init @# (arg);
+    fi
+  elseif arg<>"":
+    box_init @# (mth_tex[@] arg);
+  fi
+enddef;
+
+vardef NFR[] (text PRM) (expr lilb, rilb, ldlb, rdlb)
+  (suffix j_sty, a_sty, i_sty)=
+  %
+  % @: inference index
+  %
+  if known prm_num[@]:
+    drv_errhelp "An index can be used only once to declare an inference.";
+    drv_errmessage (decimal @)&" has been used already as an inference index";
+  else:
+    %
+    % PRM: list of premise indices
+    %
+    save prm_rnk;
+    numeric prm_rnk;
+    prm_rnk:=0;
+    for prm_idx=PRM:
+      if prm_idx=@:
+        drv_errhelp "An inference index can not be used"&
+          " as one of its own premise indices.";
+        drv_errmessage "the inference index "&(decimal prm_idx)&
+          " is used as one of its own premise indices";
+      elseif known ccl[prm_idx]:
+        drv_errhelp "An index can be used only once as a premise index.";
+        drv_errmessage (decimal prm_idx)&" has been used already as a"&
+          " premise index for inference declaration "&(decimal ccl[prm_idx]);
+      else:
+        if known prm_num[prm_idx]:
+          %
+          % roots list update
+          %
+          save root_idx;
+          numeric root_idx;
+          root_idx:=0;
+          forever:
+            exitif root[root_idx]=prm_idx;
+            root_idx:=root_idx+1;
+          endfor
+          forever:
+            exitif root_idx=root_num-1;
+            root[root_idx]:=root[root_idx+1];
+            root_idx:=root_idx+1;
+          endfor
+          root_num:=root_num-1;
+        fi
+        ccl[prm_idx]:=@;
+        prm[@][prm_rnk]:=prm_idx;
+        prm_rnk:=prm_rnk+1;
+      fi
+    endfor
+    prm_num[@]:=prm_rnk;
+    if known ccl[@]:
+      %
+      % cycle detection
+      %
+      save ccl_idx, ccl_str;
+      numeric ccl_idx;
+      string ccl_str;
+      ccl_idx:=@;
+      ccl_str:=decimal ccl_idx;
+      forever:
+        ccl_idx:=ccl[ccl_idx];
+        if ccl_idx>=0:
+          ccl_str:=(decimal ccl_idx)&", "&ccl_str;
+        fi
+        exitif (unknown ccl[ccl_idx]) or (ccl_idx=@);
+      endfor
+      if ccl_idx=@:
+        drv_errhelp  "Inferences declarations can not be cyclic.";
+        drv_errmessage "inference declaration "&(decimal @)&" creates a"&
+          " cycle of inferences (indices "&ccl_str&" from conclusions to"&
+          " premises)";
+      fi
+    else:
+      root[root_num]:=@;
+      root_num:=root_num+1;
+    fi
+    %
+    % lilb, rilb: inference labels
+    %
+    opt_init[ilb_sty[drv_sty]] l_ilb[@] lilb;
+    opt_init[ilb_sty[drv_sty]] r_ilb[@] rilb;
+    %
+    % ldlb, rdlb: delimiter labels
+    %
+    opt_init[dlb_sty[drv_sty]] l_dlb[@] ldlb;
+    opt_init[dlb_sty[drv_sty]] r_dlb[@] rdlb;
+    %
+    % j_sty, a_sty and i_sty: junction, alignment and inference styles
+    %
+    jct_sty[@]:=check_junction_style (j_sty, drv_jct_sty);
+    alg_sty[@]:=check_alignment_style (a_sty, drv_alg_sty);
+    iln_sty[@]:=check_path_style (i_sty, drv_iln_sty);
+    if drv_boxmode_on:
+      boxed[@]:=true;
+    fi
+  fi
+enddef;
+
+vardef DCL[] (text PRM) (expr lilb, rilb, ldlb, rdlb)
+  (suffix j_sty, a_sty, i_sty) text SUB=
+    NFR[@] (PRM) (lilb, rilb, ldlb, rdlb, j_sty, a_sty, i_sty);
+    jgm[@] SUB;
+enddef;
+
+vardef MVD[] (expr inf_num, lplb, rplb) (suffix a_sty, p_sty)=
+  if inf_num<1:
+    drv_errhelp "The minimal value is 1.";
+    drv_errmessage (decimal inf_num)&" is not a valid number of inference"&
+      " steps";
+  else:
+    save aux_idx, aux_sty, phm_jdg;
+    numeric aux_idx, aux_sty;
+    picture phm_jdg;
+    aux_sty:=check_path_style (p_sty, drv_phm_sty);
+    phm_jdg:=nullpicture;
+    setbounds phm_jdg to (0, 0)--(iln_hg[aux_sty]-iln_dp[aux_sty], 0)--cycle;
+    aux_idx:=@;
+    for i=1 upto inf_num:
+      phm_idx:=phm_idx-1;
+      box_init jdg[phm_idx] (phm_jdg);
+      sbj_num[phm_idx]:=0;
+      NFR[phm_idx] (aux_idx) ("", "", "", "", 0, a_sty, 0);
+      aux_idx:=phm_idx;
+    endfor
+    src[@]:=phm_idx;
+    tgt[phm_idx]:=@;
+    phm_sty[phm_idx]:=aux_sty;
+    %
+    % lplb, rplb: phantom steps labels
+    %
+    opt_init[plb_sty[drv_sty]] l_plb[phm_idx] lplb;
+    opt_init[plb_sty[drv_sty]] r_plb[phm_idx] rplb;
+    phm_idx
+  fi
+enddef;
+
+vardef bxd[]=
+  boxed[@]:=true;
+  @
+enddef;
+
+%
+% Optional labels & shorthands
+%
+
+numeric drv_jct_sty;	% default junction style
+string  drv_alg_sty;	% default junction style
+numeric drv_iln_sty;	% default inference line path-style
+numeric drv_phm_sty;	% default phantom steps path-style
+
+boolean drv_left_ilb;	% inference labels on the left
+boolean drv_left_dlb;	% delimiter labels (hence delimiters) on the left
+boolean drv_left_plb;	% phantom steps labels on the left
+
+vardef arg_type expr arg=
+  if picture arg:
+    "picture"
+  else:
+    "string"
+  fi
+enddef;
+
+vardef opt_lbls @# (text LBL) expr left_lbls=
+  save lbl_num, fst_lbl, snd_lbl;
+  numeric lbl_num;
+  lbl_num:=0;
+  for lbl=LBL:
+    if lbl_num=0:
+      scantokens (arg_type lbl) fst_lbl;
+      fst_lbl:=lbl;
+    elseif lbl_num=1:
+      scantokens (arg_type lbl) snd_lbl;
+      snd_lbl:=lbl;
+    else:
+      drv_errhelp "At most two labels can be specified:"&
+        " a left one and a right one.";
+      drv_errmessage "more than two labels have been specified";
+    fi
+    lbl_num:=lbl_num+1;
+  endfor
+  if lbl_num=0:
+    string @#.l;
+    string @#.r;
+    @#.l:="";
+    @#.r:="";
+  elseif lbl_num=1:
+    if left_lbls:
+      scantokens (arg_type fst_lbl) @#.l;
+      string @#.r;
+      @#.l:=fst_lbl;
+      @#.r:="";
+    else:
+      string @#.l;
+      scantokens (arg_type fst_lbl) @#.r;
+      @#.l:="";
+      @#.r:=fst_lbl;
+    fi
+  else:
+    scantokens (arg_type fst_lbl) @#.l;
+    scantokens (arg_type snd_lbl) @#.r;
+    @#.l:=fst_lbl;
+    @#.r:=snd_lbl;
+  fi
+enddef;
+
+vardef NFR_opt[] (text PRM) (text ILB) (text DLB)
+  (suffix j_sty, a_sty, i_sty)=
+    opt_lbls ilb (ILB) drv_left_ilb;
+    opt_lbls dlb (DLB) drv_left_dlb;
+    NFR[@] (PRM) (ilb.l, ilb.r, dlb.l, dlb.r, j_sty, a_sty, i_sty);
+enddef;
+
+vardef DCL_opt[] (text PRM) (text ILB) (text DLB)
+  (suffix j_sty, a_sty, i_sty) text SUB=
+    NFR_opt[@] (PRM) (ILB) (DLB) (j_sty, a_sty, i_sty);
+    jgm[@] SUB;
+enddef;
+
+vardef MVD_opt[] (expr inf_num) (text PLB) (suffix a_sty, p_sty)=
+  opt_lbls plb (PLB) drv_left_plb;
+  MVD[@] (inf_num, plb.l, plb.r, a_sty, p_sty)
+enddef;
+
+% Nfr, Dcl & Mvd
+
+vardef Nfr[] (text PRM) (expr ilb, ldlb, rdlb) (suffix i_sty)=
+  NFR_opt[@] (PRM) (ilb) (ldlb, rdlb) (_, _, i_sty);
+enddef;
+
+vardef Dcl[] (text PRM) (expr ilb, ldlb, rdlb) (suffix i_sty) text SUB=
+  Nfr[@] (PRM) (ilb, ldlb, rdlb, i_sty);
+  jgm[@] SUB;
+enddef;
+
+vardef Mvd[] (expr inf_num, lplb, rplb) (suffix p_sty)=
+  MVD[@] (inf_num, lplb, rplb, _, p_sty)
+enddef;
+
+% nfr, dcl & mvd
+
+vardef nfr[] (text PRM) (expr ilb) (suffix i_sty)=
+  NFR_opt[@] (PRM) (ilb) () (_, _, i_sty);
+enddef;
+
+vardef dcl[] (text PRM) (expr ilb) (suffix i_sty) text SUB=
+  nfr[@] (PRM) (ilb, i_sty);
+  jgm[@] SUB;
+enddef;
+
+vardef mvd[] (expr inf_num) (suffix p_sty)=
+  MVD_opt[@] (inf_num) () (_, p_sty)
+enddef;
+
+
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+%
+% Pictured paths
+%
+
+vardef dotted_aux (expr pth, dot_wd, dots_dist)=
+  save pth_len, pct;
+  numeric pth_len;
+  picture pct;
+  pth_len:=arclength pth;
+  pct:=nullpicture;
+  if dots_dist>0:
+    stp_num:=round ((pth_len-dot_wd)/dots_dist);
+    if stp_num>0:
+      stp_len:=(pth_len-dot_wd)/stp_num;
+      addto pct doublepath pth dashed dashpattern (on 0 off stp_len)
+        shifted (dot_wd/2, 0) withpen pencircle scaled dot_wd;
+    fi
+  fi
+  pct
+enddef;
+
+primarydef pth dotted wd_dist=
+  dotted_aux(pth, xpart wd_dist, ypart wd_dist)
+enddef;
+
+vardef expanded_aux (expr pth, scl, dir, stp_len)=
+  save pth_len, aux_len;
+  numeric pth_len, aux_len;
+  pth_len:=arclength pth;
+  if (stp_len>0) and (pth_len>stp_len):
+    aux_len:=pth_len/(pth_len div stp_len);
+    point arctime 0 of pth of pth shifted
+      (unitvector direction arctime 0 of pth of pth
+        rotated dir scaled scl)..
+          {direction arctime 0 of pth of pth}
+    for i=aux_len step aux_len until pth_len-aux_len:
+      point arctime i of pth of pth shifted
+        (unitvector direction arctime i of pth of pth
+          rotated dir scaled scl)
+            {direction arctime i of pth of pth}..
+    endfor
+    point arctime pth_len of pth of pth shifted
+      (unitvector direction arctime pth_len of pth of pth
+        rotated dir scaled scl)
+          {direction arctime pth_len of pth of pth}
+  else:
+    pth
+  fi
+enddef;
+
+primarydef pth expanded scl_dir_len=
+  expanded_aux (pth,
+    redpart scl_dir_len, greenpart scl_dir_len, bluepart scl_dir_len)
+enddef;
+
+vardef waved_aux (expr pth, amp)=
+  save pth_len, mid;
+  numeric pth_len, mid;
+  pth_len:=arclength pth;
+  if (amp>0) and (pth_len>2(1+sqrt 5)*amp):
+    mid:=pth_len/(2(pth_len div (2(1+sqrt 5)*amp)));
+    point arctime 0 of pth of pth shifted
+      (unitvector direction arctime 0 of pth of pth
+        rotated -90 scaled amp)
+          {direction arctime 0 of pth of pth}
+    for i=mid step 2mid until pth_len:
+    ..point arctime i of pth of pth shifted
+        (unitvector direction arctime i of pth of pth
+          rotated 90 scaled amp)
+            {direction arctime i of pth of pth}
+    ..point arctime i+mid of pth of pth shifted
+        (unitvector direction arctime i+mid of pth of pth
+          rotated -90 scaled amp)
+            {direction arctime i+mid of pth of pth}
+    endfor
+  else:
+    pth
+  fi
+enddef;
+
+primarydef pth waved amp=
+  waved_aux(pth, amp)
+enddef;
+
+vardef drv_styled_aux[] expr pth=
+  save sty_idx, pth_len, pct;
+  numeric sty_idx, pth_len;
+  picture pct;
+  sty_idx:=check_path_style (@, 1);
+  pth_len:=arclength pth;
+  pct:=nullpicture;
+  if sty_idx=1:
+    interim linecap:=butt;
+    addto pct doublepath pth withpen drv_pen;
+  elseif sty_idx=2:
+    interim linecap:=butt;
+    addto pct doublepath pth
+      expanded (1.25rul_thk[drv_sty],  90, rul_thk[drv_sty])
+      withpen drv_pen;
+    addto pct doublepath pth
+      expanded (1.25rul_thk[drv_sty], -90, rul_thk[drv_sty])
+      withpen drv_pen;
+  elseif sty_idx=3:
+    addto pct also pth dotted (rul_thk[drv_sty], 2rul_thk[drv_sty]);
+  elseif sty_idx=4:
+    if rul_thk[drv_sty]>0:
+      interim linecap:=butt;
+      save dsh_num, dsh_len;
+      numeric dsh_num, dsh_len;
+      dsh_num:=round(pth_len/(3rul_thk[drv_sty]));
+      dsh_len:=
+        if odd dsh_num:
+          pth_len/dsh_num
+        else:
+          pth_len/(dsh_num+1)
+        fi;
+      addto pct doublepath pth dashed dashpattern(on dsh_len off dsh_len)
+        withpen drv_pen;
+    fi
+  elseif sty_idx=5:
+    interim linecap:=butt;
+    addto pct doublepath pth
+      waved 1.25rul_thk[drv_sty] withpen drv_pen;
+  elseif (sty_idx=6) and (pth_len>0):
+    addto pct also pth dotted (pdt_hg[drv_sty], pdt_wd[drv_sty]);
+  fi
+  pct
+enddef;
+
+primarydef pth drv_styled sty=
+  drv_styled_aux[sty] pth
+enddef;
+
+
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+%
+% Delimiters
+%
+
+%
+% 1. Global parameters
+%
+
+string drv_l_dlm; % left delimiter LaTeX code
+string drv_r_dlm; % right delimiter LaTeX code
+
+%
+% 2. Macros
+%
+
+vardef minmax_y[]=(
+  if drv_bot_roots:
+    if known ccl[@]:
+      ypart jdg[@].c-num_hg+iln_hg[(iln_sty[ccl[@]])]
+        +min_clr_scl*min_clr[drv_sty]/2
+    else:
+      smin_y[@]-min_clr_scl*min_clr[drv_sty]
+    fi,
+    smax_y[@]+min_clr_scl*min_clr[drv_sty]
+  else:
+    smin_y[@]-min_clr_scl*min_clr[drv_sty],
+    if known ccl[@]:
+      ypart jdg[@].c-den_dp-iln_hg[(iln_sty[ccl[@]])]
+        -min_clr_scl*min_clr[drv_sty]/2
+    else:
+      smax_y[@]+min_clr_scl*min_clr[drv_sty]
+    fi
+  fi)
+enddef;
+
+vardef delim @# expr dlm_len=
+  save rule_str, dlm_str, dlm_pct, dlm_dp;
+  string rule_str, dlm_str;
+  picture dlm_pct;
+  numeric dlm_dp;
+  rule_str:="\rule{0bp}{"&(decimal(dlm_len/2+axis_hg[drv_sty]))&"bp}";
+  dlm_str:=
+    if str @#="l":
+      "\left"&drv_l_dlm&rule_str&"\right."
+    else:
+      "\left."&rule_str&"\right"&drv_r_dlm
+    fi;
+  dlm_pct:=mth_tex[drv_sty] dlm_str;
+  dlm_dp:=depth dlm_pct;
+  if dlm_dp=0:
+    nullpicture
+  else:
+    begingroup
+      setbounds dlm_pct to
+        (xpart llcorner dlm_pct,  dlm_dp)
+      --(xpart ulcorner dlm_pct, -dlm_dp)
+      --(xpart urcorner dlm_pct, -dlm_dp)
+      --(xpart lrcorner dlm_pct,  dlm_dp)
+      --cycle;
+      dlm_pct yscaled (dlm_len/(2*height dlm_pct))
+    endgroup
+  fi
+enddef;
+
+
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+%
+% Checking, building, freezing (very inefficient, to be improved)
+%
+
+%
+% 1. Global parameters
+%
+
+numeric min_clr_scl;		%
+numeric prm_skp_scl;		%
+numeric jdg_skp_scl;		%
+numeric ilb_skp_scl;		%
+numeric plb_skp_scl;		%
+
+boolean drv_bot_roots;		%
+boolean drv_boxmode_on;		%
+boolean drv_fractionmode_on;	%
+string  drv_axis_ref;		%
+
+%
+% 2. Macros
+%
+
+%
+% Checking
+%
+
+vardef fraction_inference[]=
+      (prm_num[@]=0)
+  and (iln_sty[@]=0)
+  and (unknown l_ilb[@])
+  and (unknown r_ilb[@])
+  and drv_fractionmode_on
+enddef;
+
+vardef drv_check_root[]=
+  if unknown jdg[@]:
+    drv_errhelp "An index must be used to declare a both a judgment and an"&
+      " inference.";
+    drv_errmessage (decimal @)&" has been used as an inference index but not"&
+      " as a judgment index";
+  elseif unknown prm_num[@]:
+    drv_errhelp "An index must be used to declare a both a judgment and an"&
+      " inference.";
+    drv_errmessage (decimal @)&" has been used as a judgment index but not"&
+      " as an inference index";
+  else:
+    save i_sty, prm_idx;
+    numeric i_sty, prm_idx;
+    i_sty:=iln_sty[@];
+    for prm_rnk=0 upto prm_num[@]-1:
+      prm_idx:=prm[@][prm_rnk];
+      drv_check_root[prm_idx];
+      %
+      % numerators and denominators clearances
+      % The TEXbook, Appendix G, Rule 15d.
+      %
+      if drv_bot_roots:
+        num_hg:=max(num_hg,
+          iln_hg[i_sty]+min_clr_scl*min_clr[drv_sty]-jdg[prm_idx].dp);
+      else:
+        den_dp:=min(den_dp,
+          iln_dp[i_sty]-min_clr_scl*min_clr[drv_sty]-jdg[prm_idx].hg);
+      fi
+    endfor
+    if not fraction_inference[@]:
+      if drv_bot_roots:
+        den_dp:=min(den_dp,
+          iln_dp[i_sty]-min_clr_scl*min_clr[drv_sty]-jdg[@].hg);
+      else:
+        num_hg:=max(num_hg,
+          iln_hg[i_sty]+min_clr_scl*min_clr[drv_sty]-jdg[@].dp);
+      fi
+    fi
+    if unknown boxed[@]:
+      boxed[@]:=false;
+    fi
+  fi
+enddef;
+
+vardef drv_check=
+  if root_num=0:
+    drv_errhelp "Well ...";
+    drv_errmessage "no inference has been declared";
+  else:
+    save root_idx;
+    numeric root_idx;
+    root_idx:=root[0];
+    drv_check_root[root_idx];
+    if root_num>1:
+      save root_str;
+      string root_str;
+      root_str:=decimal root_idx;
+      for idx=1 upto root_num-1:
+        root_idx:=root[idx];
+        drv_check_root[root_idx];
+        root_str:=root_str&", "&(decimal root_idx);
+      endfor
+      drv_message "warning, multiple root indices ("&root_str&").";
+    fi
+  fi
+  drv_checked:=true;
+enddef;
+
+%
+% Building
+%
+
+vardef drv_build_root[]=
+  %
+  % premises junction (from left to right)
+  %
+  for prm_rnk=0 upto  prm_num[@]-1:
+    drv_build_root[prm[@][prm_rnk]];
+    if prm_rnk>0:
+      save ll_idx, lr_idx, rl_idx, rr_idx;
+      save lmax_x, rmin_x, min_skp;
+      numeric ll_idx, lr_idx, rl_idx, rr_idx;
+      numeric lmax_x, rmin_x, min_skp;
+      ypart jdg[prm[@][prm_rnk-1]].c=ypart jdg[prm[@][prm_rnk]].c;
+      ll_idx:=prm[@][0];
+      lr_idx:=prm[@][prm_rnk-1];
+      rl_idx:=prm[@][prm_rnk];
+      rr_idx:=prm[@][prm_rnk];
+      lmax_x:=imax_x[lr_idx];
+      rmin_x:=imin_x[rl_idx];
+      min_skp[0]:=rmin_x-lmax_x;
+      forever:
+        exitif (unknown r_prm[lr_idx]) or (unknown l_prm[rl_idx]);
+        ll_idx:=l_prm[ll_idx];
+        lr_idx:=r_prm[lr_idx];
+        rl_idx:=l_prm[rl_idx];
+        rr_idx:=r_prm[rr_idx];
+        lmax_x:=max(lmax_x, imax_x[lr_idx]);
+        rmin_x:=min(rmin_x, imin_x[rl_idx]);
+        min_skp[0]:=min(min_skp[0], imin_x[rl_idx]-imax_x[lr_idx]);
+      endfor
+      min_skp[1]:=rmin_x-lmax_x;
+      if known r_prm[lr_idx]:
+        r_prm[rr_idx]:= r_prm[lr_idx];
+        lmax_x:=smax_x[lr_idx];
+      elseif known l_prm[rl_idx]:
+        l_prm[ll_idx]:=l_prm[rl_idx];
+        rmin_x:=smin_x[rl_idx];
+      fi
+      min_skp[2]:=rmin_x-lmax_x;
+      if jct_sty[@]<3:
+        min_skp[jct_sty[@]]=prm_skp_scl*prm_skp[drv_sty];
+      fi
+    fi
+  endfor
+  if  prm_num[@]>0:
+    l_prm[@]:=prm[@][0];
+    r_prm[@]:=prm[@][prm_num[@]-1];
+  fi
+  %
+  % judgment alignment
+  %
+  if prm_num[@]=0:
+    imin_x[@]:=xpart jdg[@].l-jdg_skp_scl*jdg_skp[jdg_sty[drv_sty]];
+    imax_x[@]:=xpart jdg[@].r+jdg_skp_scl*jdg_skp[jdg_sty[drv_sty]];
+  else:
+    save l_xref, r_xref;
+    l_xref=
+      if boxed[prm[@][0]]:
+        smin_x[prm[@][0]]
+      else:
+        xpart jdg[prm[@][0]].l
+      fi;
+    r_xref=
+      if boxed[prm[@][prm_num[@]-1]]:
+        smax_x[prm[@][prm_num[@]-1]]
+      else:
+        xpart jdg[prm[@][prm_num[@]-1]].r
+      fi;
+    if alg_sty[@]="l":
+      xpart jdg[@].l=l_xref;
+    elseif alg_sty[@]="c":
+      xpart jdg[@].c=(l_xref+r_xref)/2;
+    elseif alg_sty[@]="r":
+      xpart jdg[@].r=r_xref;
+    fi
+    imin_x[@]:=min(xpart jdg[@].l, l_xref)
+          -jdg_skp_scl*jdg_skp[jdg_sty[drv_sty]];
+    imax_x[@]:=max(xpart jdg[@].r, r_xref)
+          +jdg_skp_scl*jdg_skp[jdg_sty[drv_sty]];
+  fi
+  %
+  % inference line
+  %
+  save iln_wd, iln_pct;
+  numeric iln_wd;
+  picture iln_pct;
+  iln_wd:=imax_x[@]-imin_x[@];
+  iln_pct:=((0, 0)--(iln_wd, 0)) drv_styled iln_sty[@];
+  setbounds iln_pct to
+    (0, ypart llcorner iln_pct)
+  --(0, ypart ulcorner iln_pct)
+  --(iln_wd, ypart ulcorner iln_pct)
+  --(iln_wd, ypart llcorner iln_pct)
+  --cycle; % ! `linecap:=butt' and `linecap:=squared' -> same bounding box !
+  box_init iln[@] (iln_pct);
+  xpart iln[@].c=(imin_x[@]+imax_x[@])/2;
+  %
+  % orientation, smin_y & smax_y
+  %
+  if drv_bot_roots:
+    ypart iln[@].c=ypart jdg[@].c-den_dp;
+    smin_y[@]:=ypart jdg[@].c+jdg[@].dp;
+    smax_y[@]:=
+      if iln_sty[@]=0:
+        ypart jdg[@].c+jdg[@].hg
+      else:
+        ypart iln[@].c+iln[@].hg
+      fi;
+    if prm_num[@]>0:
+      ypart iln[@].c=ypart jdg[prm[@][0]].c-num_hg;
+      for prm_rnk=0 upto prm_num[@]-1:
+        smax_y[@]:=max(smax_y[@], smax_y[prm[@][prm_rnk]]);
+      endfor;
+    fi
+  else:
+    ypart iln[@].c=ypart jdg[@].c-num_hg;
+    smin_y[@]:=
+      if iln_sty[@]=0:
+        ypart jdg[@].c+jdg[@].dp
+      else:
+        ypart iln[@].c+iln[@].dp
+      fi;
+    smax_y[@]:=ypart jdg[@].c+jdg[@].hg;
+    if prm_num[@]>0:
+      ypart iln[@].c=ypart jdg[prm[@][0]].c-den_dp;
+      for prm_rnk=0 upto prm_num[@]-1:
+        smin_y[@]:=min(smin_y[@], smin_y[prm[@][prm_rnk]]);
+      endfor;
+    fi
+  fi
+  %
+  % inference labels
+  %
+  if known l_ilb[@]:
+    l_ilb[@].r=iln[@].l shifted (-ilb_skp_scl*ilb_skp[drv_sty], 0);
+    imin_x[@]:=xpart l_ilb[@].l;
+    smin_y[@]:=min(smin_y[@], ypart l_ilb[@].c+l_ilb[@].dp);
+    smax_y[@]:=max(smax_y[@], ypart l_ilb[@].c+l_ilb[@].hg);
+  fi
+  if known r_ilb[@]:
+    r_ilb[@].l=iln[@].r shifted (ilb_skp_scl*ilb_skp[drv_sty], 0);
+    imax_x[@]:=xpart r_ilb[@].r;
+    smin_y[@]:=min(smin_y[@], ypart r_ilb[@].c+r_ilb[@].dp);
+    smax_y[@]:=max(smax_y[@], ypart r_ilb[@].c+r_ilb[@].hg);
+  fi
+  %
+  % phantom steps
+  %
+  if known tgt[@]:
+    save phm_pth, phm_pct;
+    path phm_pth;
+    picture phm_pct;
+    save top_y, mid_y, bot_y;
+    numeric top_y, bot_y;
+    if drv_bot_roots:
+      bot_y:=xpart minmax_y[@]+min_clr_scl*min_clr[drv_sty]/2;
+      top_y:=xpart minmax_y[tgt[@]];
+    else:
+      bot_y:=ypart minmax_y[tgt[@]];
+      top_y:=ypart minmax_y[@]-min_clr_scl*min_clr[drv_sty]/2;
+    fi
+    mid_y:=(top_y+bot_y)/2;
+    phm_pth:=(0, (bot_y-top_y)/2)--(0, (top_y-bot_y)/2);
+    phm_pct:=phm_pth drv_styled phm_sty[@];
+    box_init phm[@] (phm_pct shifted ((width phm_pct)/2, 0));
+    phm[@].c=(xpart jdg[@].c, mid_y);
+    imin_x[@]:=min(imin_x[@], xpart phm[@].l);
+    imax_x[@]:=max(imax_x[@], xpart phm[@].r);
+    %
+    % phantom steps labels
+    %
+    if known l_plb[@]:
+      l_plb[@].r=phm[@].l shifted (-plb_skp[drv_sty], 0);
+      imin_x[@]:=min(imin_x[@], xpart l_plb[@].l);
+    fi
+    if known r_plb[@]:
+      r_plb[@].l=phm[@].r shifted ( plb_skp[drv_sty], 0);
+      imax_x[@]:=max(imax_x[@], xpart r_plb[@].r);
+    fi
+  fi
+  %
+  % smin_x & smax_x
+  %
+  smin_x[@]:=imin_x[@];
+  smax_x[@]:=imax_x[@];
+  for prm_rnk=0 upto prm_num[@]-1:
+    smin_x[@]:=min(smin_x[@], smin_x[prm[@][prm_rnk]]);
+    smax_x[@]:=max(smax_x[@], smax_x[prm[@][prm_rnk]]);
+  endfor
+  %
+  % delimiters
+  %
+  if known l_dlb[@] or known r_dlb[@]:
+    save idx, mmy, min_y, max_y;
+    numeric idx, min_y, max_y;
+    pair mmy;
+    mmy:=minmax_y[@];
+    min_y:=xpart mmy;
+    max_y:=ypart mmy;
+    if known l_dlb[@]:
+      box_init l_dlm[@] (delim l (max_y-min_y));
+      l_dlm[@].r=(smin_x[@], (max_y+min_y)/2);
+      l_dlb[@].r=l_dlm[@].l;
+      smin_x[@]:=xpart l_dlb[@].l;
+    fi
+    if known r_dlb[@]:
+      box_init r_dlm[@] (delim r (max_y-min_y));
+      r_dlm[@].l=(smax_x[@], (max_y+min_y)/2);
+      r_dlb[@].l=r_dlm[@].r;
+      smax_x[@]:=xpart r_dlb[@].r;
+    fi
+  fi
+  if (known l_dlb[@]) or boxed[@]:
+    idx:=@;
+    forever:
+      imin_x[idx]:=smin_x[@];
+      exitif unknown l_prm[idx];
+      idx:=l_prm[idx];
+    endfor
+  fi
+  if (known r_dlb[@]) or boxed[@]:
+    idx:=@;
+    forever:
+      imax_x[idx]:=smax_x[@];
+      exitif unknown r_prm[idx];
+      idx:=r_prm[idx];
+    endfor
+  fi
+enddef;
+
+vardef drv_build=
+  if not drv_checked:
+    drv_check;
+  fi
+  for idx=0 upto root_num-1:
+    drv_build_root[root[idx]];
+  endfor
+  drv_built:=true;
+enddef;
+
+%
+% Freezing
+%
+
+vardef drv_freeze_root[]=
+  for prm_rnk=0 upto prm_num[@]-1:
+    drv_freeze_root[prm[@][prm_rnk]];
+  endfor
+  for sbj_rnk=0 upto sbj_num[@]-1:
+    box_freeze sbj[@][sbj_rnk];
+  endfor
+  forsuffixes sfx=
+    iln, jdg, phm,
+    l_dlb, l_dlm, l_ilb, l_plb,
+    r_dlb, r_dlm, r_ilb, r_plb:
+      if known sfx[@]:
+        box_freeze sfx[@];
+      fi
+  endfor
+enddef;
+
+vardef drv_freeze=
+  if not drv_built:
+    drv_build;
+  fi
+  save root_idx;
+  numeric root_idx;
+  root_idx:=root[0];
+  if unknown iln[root_idx].c:
+    %
+    % default math axis
+    %
+    if drv_axis_ref="iln":
+      iln[root_idx].c=(0, axis_hg[drv_sty]);
+    else: % drv_axis_ref="jdg"
+      jdg[root_idx].c=(0, axis_hg[drv_sty]);
+    fi
+    drv_freeze_root[root_idx];
+  fi
+  for idx=1 upto root_num-1:
+    root_idx:=root[idx];
+    if unknown iln[root_idx].c:
+      smin_x[root_idx]=smax_x[root[idx-1]]+prm_skp_scl*prm_skp[drv_sty];
+      ypart iln[root_idx].c=ypart iln[root[idx-1]].c;
+    fi
+    drv_freeze_root[root_idx];
+  endfor
+  drv_frozen:=true;
+enddef;
+
+
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+%
+% Derivation tree pictures
+%
+
+%
+% 1. Global parameters
+%
+
+boolean drv_proofmode_on;	%
+color prf_clr;			%
+color jdg_clr;			%
+color sbj_clr;			%
+
+prf_clr:=.75background;		% arbitrary
+jdg_clr:=red;			% arbitrary
+sbj_clr:=blue;			% arbitrary
+
+%
+% 2. Macros
+%
+
+vardef drv_tree_addto @# (expr idx) text draw_options=
+  for prm_rnk=0 upto prm_num[idx]-1:
+    drv_tree_addto @# (prm[idx][prm_rnk]) draw_options;
+  endfor
+  forsuffixes sfx=
+    jdg, phm,
+    l_dlb, l_dlm, l_ilb, l_plb,
+    r_dlb, r_dlm, r_ilb, r_plb:
+      if known sfx[idx]:
+        addto @# also sfx[idx] draw_options;
+      fi
+  endfor
+  if iln_sty[idx]>0:
+      addto @# also iln[idx] draw_options;
+  fi
+enddef;
+
+vardef tt_nat[] expr nat= % typewriter typeface naturals
+  save nat_aux, nat_pct_wd, dgt_num, nat_pct;
+  numeric nat_aux, nat_pct_wd, dgt_num;
+  picture nat_pct;
+  nat_aux:=abs nat;
+  nat_pct:=nullpicture;
+  nat_pct_wd:=0;
+  dgt_num:=1;
+  forever:
+    exitif nat_aux div (10**dgt_num)=0;
+    dgt_num:=dgt_num+1;
+  endfor
+  for rnk:=1 upto dgt_num:
+    addto nat_pct also tt_dgt[@][nat_aux div (10**(dgt_num-rnk))]
+      shifted (nat_pct_wd, 0);
+    nat_pct_wd:=width nat_pct;
+    nat_aux:=nat_aux mod (10**(dgt_num-rnk));
+  endfor
+  nat_pct shifted (0, -axis_hg[@])
+enddef;
+
+vardef prf_tree_addto @# expr idx=
+  for prm_rnk=0 upto prm_num[idx]-1:
+    prf_tree_addto @# (prm[idx][prm_rnk]);
+  endfor
+  if idx>=0:
+    box_init jdg_prf[idx] (tt_nat[2] idx);
+    jdg_prf[idx].r=jdg[idx].l;
+    box_freeze jdg_prf[idx];
+    addto @# also jdg_prf[idx] withcolor jdg_clr;
+    addto @# doublepath jdg[idx].c withcolor jdg_clr
+      withpen pencircle scaled (2*pdt_hg[drv_sty]);
+  fi
+  for sbj_rnk=0 upto sbj_num[idx]-1:
+    box_init sbj_prf[idx][sbj_rnk] (tt_nat[3] sbj_rnk);
+    if odd sbj_rnk:
+      sbj_prf[idx][sbj_rnk].c shifted (0, sbj_prf[idx][sbj_rnk].hg)=
+        sbj[idx][sbj_rnk].c
+          shifted (0, -den_dp-min_clr_scl*min_clr[drv_sty]/2);
+    else:
+      sbj_prf[idx][sbj_rnk].c shifted (0, sbj_prf[idx][sbj_rnk].dp)=
+        sbj[idx][sbj_rnk].c
+          shifted (0, -num_hg+min_clr_scl*min_clr[drv_sty]/2);
+    fi
+    box_freeze sbj_prf[idx][sbj_rnk];
+    addto @# also sbj_prf[idx][sbj_rnk] withcolor sbj_clr;
+    addto @# doublepath sbj[idx][sbj_rnk].c withcolor sbj_clr
+      withpen pencircle scaled pdt_hg[drv_sty];
+  endfor
+enddef;
+
+vardef drv_tree=
+  save pct;
+  picture pct;
+  pct:=nullpicture;
+  if not drv_frozen:
+    drv_freeze;
+  fi
+  for root_idx=0 upto root_num-1:
+    if drv_proofmode_on:
+      drv_tree_addto pct (root[root_idx]) withcolor prf_clr;
+      prf_tree_addto pct (root[root_idx]);
+    else:
+      drv_tree_addto pct (root[root_idx]);
+    fi
+  endfor
+  pct
+enddef;
+
+vardef drv_bbox[]=
+  save min_x, max_x, mmy, min_y, max_y;
+  pair mmy;
+  numeric min_x, max_x, max_y, min_y;
+  if not drv_frozen:
+    drv_freeze;
+  fi
+  min_x:=
+    if known l_dlm[@].r:
+      xpart l_dlm[@].r
+    else:
+      smin_x[@]
+    fi-jdg_skp_scl*jdg_skp[jdg_sty[drv_sty]];
+  max_x:=
+    if known r_dlm[@].l:
+      xpart l_dlm[@].l
+    else:
+      smax_x[@]
+    fi+jdg_skp_scl*jdg_skp[jdg_sty[drv_sty]];
+  mmy:=minmax_y[@];
+  min_y:=xpart mmy;
+  max_y:=ypart mmy;
+  (min_x, min_y)--
+  (min_x, max_y)--
+  (max_x, max_y)--
+  (max_x, min_y)--
+  cycle
+enddef;
+
+vardef mth_axis @# (suffix ref_sfx) (expr idx)=
+  if not drv_frozen:
+    drv_freeze;
+  fi
+  if unknown prm_num[idx]:
+    drv_errhelp "An index must be used to declare an inference before it is"&
+      " used to set the math axis of a picture.";
+    drv_errmessage "no inference has been declared using index "&(decimal idx);
+  else:
+    save ref_str, yref;
+    string ref_str;
+    numeric yref;
+    ref_str:=str ref_sfx;
+    if ref_str="iln":
+      yref:=ypart iln[idx].c;
+    elseif ref_str="jdg":
+      yref:=ypart jdg[idx].c;
+    elseif ref_str="dlm":
+      if known l_dlm[idx]:
+        yref:=ypart l_dlm[idx].c;
+      elseif known r_dlm[idx]:
+        yref:=ypart r_dlm[idx].c;
+      else:
+        drv_errhelp "Well ...";
+        drv_errmessage "no delimiter is attached to inference "&(decimal idx);
+      fi
+    else:
+      drv_errhelp "Valid identifiers are"&
+        " iln (inference line axis),"&
+        " jdg (judgment math-axis) and"&
+        " dlm (delimiter axis).";
+      drv_errmessage (ref_str&" is not a valid reference type identifier");
+    fi
+    if known yref:
+      @#:=@# shifted (0, axis_hg[drv_sty]-yref);
+    fi
+  fi
+enddef;
+
+vardef drv_axis (suffix ref) (expr idx)=
+  mth_axis currentpicture (ref, idx);
+enddef;
+
+
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+%
+% Tunings
+%
+
+vardef check_math_style (expr sty_str, default)=
+  if sty_str="\displaystyle":
+    0
+  elseif sty_str="\textstyle":
+    1
+  elseif sty_str="\scriptstyle":
+    2
+  elseif sty_str="\scriptscriptstyle":
+    3
+  else:
+    begingroup
+      drv_errhelp "Valid commands are"&
+        " \displaystyle,"&
+        " \textstyle,"&
+        " \scriptstyle and"&
+        " \scriptscriptstyle.";
+      drv_errmessage (sty_str&" is not a valid math-style command");
+      default
+    endgroup
+  fi
+enddef;
+
+vardef check_position_left (suffix pos_sfx) (expr default)=
+  save pos_str;
+  string pos_str;
+  pos_str:=str pos_sfx;
+  if (pos_str="l"):
+    true
+  elseif (pos_str="r"):
+    false
+  else:
+    begingroup
+      drv_errhelp "Valid identifiers are l (left) and r (right).";
+      drv_errmessage (pos_str&" is not a valid label position identifier");
+      default
+    endgroup
+  fi
+enddef;
+
+vardef check_mode_on (suffix status_sfx) (expr default)=
+  save status_str;
+  string status_str;
+  status_str:=str status_sfx;
+  if status_str="on":
+    true
+  elseif status_str="off":
+    false
+  else:
+    begingroup
+      drv_errhelp "Possible identifiers are on and off";
+      drv_errmessage (status_str&" is not a valid status identifier");
+      default
+    endgroup
+  fi
+enddef;
+
+vardef drv_math_style (suffix typ_sfx) (expr sty_str)=
+  save typ_str, sty_idx;
+  string typ_str;
+  numeric sty_idx;
+  typ_str:=str typ_sfx;
+  if  (typ_str<>"drv")
+  and (typ_str<>"jdg")
+  and (typ_str<>"ilb")
+  and (typ_str<>"dlb")
+  and (typ_str<>"plb"):
+    drv_errhelp "Valid  identifiers are"&
+      " drv (derivation tree),"&
+      " jdg (judgment),"&
+      " ilb (inference label),"&
+      " dlb (delimiter label) and"&
+      " plb (phantom steps label).";
+    drv_errmessage (sty_str&" is not a valid component identifier");
+  else:
+    sty_idx:=check_math_style (sty_str, 0);
+    if typ_str="drv":
+      drv_sty:=sty_idx;
+    else:
+      forsuffixes sfx=scantokens (typ_str&"_sty"):
+        for idx=0 upto 3:
+          sfx[idx]:=min(idx+sty_idx, 3);
+        endfor
+      endfor
+    fi
+  fi
+enddef;
+
+vardef drv_scale (suffix scl_sfx) (expr scl)=
+  save scl_str;
+  string scl_str;
+  scl_str:=str scl_sfx;
+  if scl_str="clr":
+    min_clr_scl:=scl;
+  elseif scl_str="prm":
+    prm_skp_scl:=scl;
+  elseif (scl_str="jdg") or (scl_str="jgm"): % "jgm" is deprecated
+    jdg_skp_scl:=scl;
+  elseif (scl_str="ilb") or (scl_str="lbl"): % "lbl" is deprecated
+    ilb_skp_scl:=scl;
+  else:
+    drv_errhelp "Valid identifiers are"&
+      " clr,"&
+      " prm,"&
+      " jdg and"&
+      " ilb.";
+    drv_errmessage (scl_str&" is not a valid scale identifier");
+  fi
+enddef;
+
+vardef drv_junction_style suffix sty_sfx=
+  drv_jct_sty:=check_junction_style (sty_sfx, drv_jct_sty);
+enddef;
+
+vardef drv_alignment_style suffix sty_sfx=
+  drv_alg_sty:=check_alignment_style (sty_sfx, drv_alg_sty);
+enddef;
+
+vardef drv_path_style (suffix typ_sfx, sty_sfx)=
+  save typ_str;
+  string typ_str;
+  typ_str:=str typ_sfx;
+  if typ_str="iln":
+    drv_iln_sty:=check_path_style (sty_sfx, drv_iln_sty);
+  elseif typ_str="phm":
+    drv_phm_sty:=check_path_style (sty_sfx, drv_phm_sty);
+  else:
+    drv_errhelp "Valid identifiers are"&
+      " iln (inference line) and"&
+      " phm (phantom steps path).";
+    drv_errmessage (typ_str&" is not a valid path-type identifier");
+  fi
+enddef;
+
+vardef drv_labels_position_aux (suffix typ_sfx, pos_sfx)=
+  save typ_str, idt_str, pos_str;
+  string typ_str, idt_str, pos_str;
+  typ_str:=str typ_sfx;
+  if  typ_str="ilb":
+    drv_left_ilb:=check_position_left (pos_sfx, drv_left_ilb);
+  elseif typ_str="dlb":
+    drv_left_dlb:=check_position_left (pos_sfx, drv_left_dlb);
+  elseif typ_str="plb":
+    drv_left_plb:=check_position_left (pos_sfx, drv_left_plb);
+  else:
+    drv_errhelp "Valid identifiers are"&
+      " ilb (inference label),"&
+      " dlb (delimiter label) and"&
+      " plb (phantom steps label).";
+    drv_errmessage (typ_str&" is not a valid label-type identifier");
+  fi
+enddef;
+
+vardef drv_labels_position text ARG=
+  drv_labels_position_aux if pair ARG: ARG else: (ilb, ARG) fi;
+enddef;
+
+vardef drv_roots_position suffix pos_sfx=
+  save pos_str;
+  string pos_str;
+  pos_str:=str pos_sfx;
+  if pos_str="t":
+    drv_bot_roots:=false;
+  elseif pos_str="b":
+    drv_bot_roots:=true;
+  else:
+    drv_errhelp "Valid identifiers are"&
+      " t (top) and"&
+      " b (bottom).";
+    drv_errmessage (pos_str&" is not a valid root position identifier");
+  fi
+enddef;
+
+vardef drv_axis_reference suffix ref_sfx=
+  save ref_str;
+  string ref_str;
+  ref_str:=str ref_sfx;
+  if (ref_str<>"iln") and (ref_str<>"jdg"):
+    drv_errhelp "Valid identifiers are iln (inference line axis) and"&
+      " jdg (judgment math-axis).";
+    drv_errmessage (ref_str&" is not a valid reference identifier");
+  else:
+    drv_axis_ref:=ref_str;
+  fi
+enddef;
+
+vardef drv_delimiter (suffix pos_sfx) (expr dlm_str)=
+  if check_position_left (pos_sfx, true):
+    drv_l_dlm:=dlm_str;
+  else:
+    drv_r_dlm:=dlm_str;
+  fi
+enddef;
+
+vardef drv_left_delimiter expr dlm_str=
+  drv_delimiter (l, dlm_str);
+enddef;
+
+vardef drv_right_delimiter expr dlm_str=
+  drv_delimiter (r, dlm_str);
+enddef;
+
+vardef drv_box_mode suffix status_sfx=
+  drv_boxmode_on:=check_mode_on (status_sfx, drv_boxmode_on);
+enddef;
+
+vardef drv_fraction_mode suffix status_sfx=
+  drv_fractionmode_on:=check_mode_on (status_sfx, drv_fractionmode_on);
+enddef;
+
+vardef drv_proof_mode suffix status_sfx=
+  drv_proofmode_on:=check_mode_on (status_sfx, drv_proofmode_on);
+enddef;
+
+
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+%
+% Default settings
+%
+
+drv_font_size "\normalsize";
+drv_math_style (drv, "\displaystyle");
+drv_math_style (jdg, "\textstyle");
+drv_math_style (ilb, "\scriptstyle");
+drv_math_style (dlb, "\textstyle");
+drv_math_style (plb, "\textstyle");
+drv_scale (clr, 1);
+drv_scale (prm, 1);
+drv_scale (jdg, 1);
+drv_scale (ilb, 1);
+drv_junction_style 1;
+drv_alignment_style c;
+drv_path_style (iln, 1);
+drv_path_style (phm, 3);
+drv_labels_position (ilb, r);
+drv_labels_position (dlb, l);
+drv_labels_position (plb, l);
+drv_roots_position b;
+drv_axis_reference iln;
+drv_left_delimiter "\lbrace";
+drv_right_delimiter "\rbrace";
+drv_box_mode off;
+drv_fraction_mode on;
+drv_proof_mode off;
+
+
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+%
+% LaTeX inclusion macro
+%
+% \drv includes a picture file in such a way that the baseline of the included
+% picture coincides with the baseline of the inclusion point. The code for \drv
+% was suggested by Josselin Noirel on the fr.comp.text.tex usenet group.
+%
+% \usepackage{graphicx}
+% \makeatletter
+% \def\Gin@def@bp#1\relax#2#3{\gdef#2{#3}}
+% \newsavebox{\graphicsbox}
+% \newcommand*{\drv}[1]{%
+% \sbox{\graphicsbox}{\includegraphics{#1}}%
+% \raisebox{\Gin@lly bp}%
+% {\usebox{\graphicsbox}}}
+% \makeatother
diff --git a/Master/texmf-dist/doc/metapost/drv/template/makefile b/Master/texmf-dist/doc/metapost/drv/template/makefile
new file mode 100644
index 00000000000..239bbc6a46e
--- /dev/null
+++ b/Master/texmf-dist/doc/metapost/drv/template/makefile
@@ -0,0 +1,46 @@
+MAIN=			template
+
+$(MAIN).pdf:		$(MAIN).ps
+			ps2pdf $(MAIN).ps
+
+$(MAIN).ps:		$(MAIN).tex $(MAIN)-delayed.mp
+			latex $(MAIN)
+			latex $(MAIN)
+			latex $(MAIN)
+			dvips $(MAIN) -o
+
+$(MAIN)-proof.pdf:	$(MAIN)-proof.ps
+			ps2pdf $(MAIN)-proof.ps
+
+$(MAIN)-proof.ps:	$(MAIN)-delayed.mp
+			latex $(MAIN)-proof
+			dvips $(MAIN)-proof -o
+
+$(MAIN)-delayed.mp:	$(MAIN).mp
+			$(RM) $(MAIN)-delayed.mp
+			mpost $(MAIN)
+			mpost $(MAIN)
+			mpost $(MAIN)
+
+.SILENT clean:
+			$(RM) drv.mpx
+			$(RM) $(MAIN).[0-9]*
+			$(RM) $(MAIN).aux
+			$(RM) $(MAIN).dvi
+			$(RM) $(MAIN).log
+			$(RM) $(MAIN).nav
+			$(RM) $(MAIN).out
+			$(RM) $(MAIN).toc
+			$(RM) $(MAIN)-delayed.mp
+			$(RM) $(MAIN)-delayed.mpx
+			$(RM) $(MAIN)-proof.aux
+			$(RM) $(MAIN)-proof.dvi
+			$(RM) $(MAIN)-proof.log
+			$(RM) $(MAIN)-proof.tex
+			$(RM) $(MAIN)-proof.toc
+
+cleanall:		clean
+			$(RM) $(MAIN).pdf
+			$(RM) $(MAIN).ps
+			$(RM) $(MAIN)-proof.pdf
+			$(RM) $(MAIN)-proof.ps
diff --git a/Master/texmf-dist/doc/metapost/drv/template/readme.txt b/Master/texmf-dist/doc/metapost/drv/template/readme.txt
new file mode 100644
index 00000000000..be277b760a8
--- /dev/null
+++ b/Master/texmf-dist/doc/metapost/drv/template/readme.txt
@@ -0,0 +1,17 @@
+# In order to compile the sources and to get a pdf file, use `make' or:
+
+# 1. run metapost THREE TIMES:
+mpost template.mp
+mpost template.mp
+mpost template.mp
+
+# 2. run latex (three times):
+latex template.tex
+latex template.tex
+latex template.tex
+
+# 3. run dvips (once):
+dvips template.dvi -o
+
+# 4. run ps2pdf (once):
+ps2pdf template.ps
diff --git a/Master/texmf-dist/doc/metapost/drv/template/template.mp b/Master/texmf-dist/doc/metapost/drv/template/template.mp
new file mode 100644
index 00000000000..0875f9df042
--- /dev/null
+++ b/Master/texmf-dist/doc/metapost/drv/template/template.mp
@@ -0,0 +1,131 @@
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+%
+% Structure of a MetaPost file using drv.mp
+%   1. Preamble
+%        input drv;
+%        verbatimtex %&latex
+%        <LaTeX preamble>
+%        \begin{document}
+%        etex;
+%  2. Figures
+%       <optional drv tunings>
+%       beginfig(<index>)
+%       <judgment & inference declarations>
+%       draw drv_tree;
+%       <optional extra MetaPost code>
+%       endfig;
+%  3. Postamble
+%       end
+%
+
+
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+%
+% 1. Preamble
+%
+
+input drv;
+
+verbatimtex %&latex
+
+% Any piece of code related to font selection in the preamble of
+% `template.tex' (document class, font package, font selection commands ...)
+% should be reported here.
+
+\documentclass[twoside,11pt]{article}
+\usepackage[T1]{fontenc}
+\usepackage{amsmath}
+\usepackage{amssymb}
+
+% Choose your favourite fonts combination (if available).
+% See "http://ctan.tug.org/tex-archive/info/Free_Math_Font_Survey".
+%
+%\usepackage{cmbright}			% CM text & CM Bright math
+%\usepackage{ccfonts,eulervm}		% Concrete text & Euler math
+%\usepackage{ccfonts}			% Concrete text & math
+%\usepackage[math]{iwona}		% Iwona text & math
+%\usepackage[math]{kurier}		% Kurier text & math
+%\usepackage[math]{anttor}		% Antykwa Torunska text & math
+%\usepackage{kmath,kerkis}		% Kerkis text & math
+%\usepackage{fouriernc}			% New Century Schoolbook & Fourier math
+%\usepackage{pxfonts}			% Palatino & pxfonts math
+%\usepackage{mathpazo}			% Palatino & Pazo math
+%\usepackage{mathpple}			% Palatino & Euler math
+\usepackage[varg]{txfonts}		% Times & txfonts math
+%\usepackage{mathtime}			% Times & Belleek math
+%\usepackage{mathptmx}			% Times & Symbol math
+%\usepackage{mbtimes}			% Omega Serif text & Omega math
+%\usepackage{arev}			% Arev Sans text with Arev math
+%\usepackage[charter]{mathdesign}	% Bitstream Charter & Math Design math
+%\usepackage{comicsans}			% Comic Sans text & math
+%\usepackage[garamond]{mathdesign}	% Garamond & Math Design math
+%\usepackage{fourier}			% Utopia & Fourier math
+%\usepackage[utopia]{mathdesign}	% Utopia & Math Design math
+
+\begin{document}
+etex;
+
+
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+%
+% 2. Figures
+%
+
+% Default settings
+%
+% drv_font_size "\normalsize";
+% drv_math_style (drv, "\displaystyle");
+% drv_math_style (jdg, "\textstyle");
+% drv_math_style (ilb, "\scriptstyle");
+% drv_math_style (dlb, "\textstyle");
+% drv_math_style (plb, "\textstyle");
+% drv_scale (clr, 1);
+% drv_scale (prm, 1);
+% drv_scale (jdg, 1);
+% drv_scale (ilb, 1);
+% drv_junction_style 1;
+% drv_alignment_style c;
+% drv_path_style (iln, 1);
+% drv_path_style (phm, 3);
+% drv_labels_position (ilb, r);
+% drv_labels_position (dlb, l);
+% drv_labels_position (plb, l);
+% drv_roots_position b;
+% drv_axis_reference iln;
+% drv_left_delimiter "\lbrace";
+% drv_right_delimiter "\rbrace";
+% drv_box_mode off;
+% drv_fraction_mode on;
+% drv_proof_mode off;
+
+beginfig(100)
+jgm 0 "\Gamma, \Delta, \Theta, \Pi, \Upsilon\vdash F";
+  jgm 1 "\Pi\vdash (A\to D)\to E";
+  jgm 2 "\Gamma, \Delta, \Theta, (A\to D)\to E, \Upsilon\vdash F";
+    jgm 3 "\Gamma, \Delta, \Theta\vdash A\to D";
+      jgm 4 "A, \Gamma, \Delta, \Theta\vdash D";
+        jgm 5 "A, \Gamma, \Delta\vdash B\wedge C";
+          jgm 6 "A, \Gamma\vdash B";
+          jgm 7 "\Delta\vdash C";
+        jgm 8 "B\wedge C, \Theta\vdash D";
+    jgm 9 "E, \Upsilon\vdash F";
+nfr 0 (1, 2) ("\text{cut}", 1);
+  nfr 1 () ("\pi", 4);
+  nfr 2 (3, 9) ("\to_L", 1);
+    nfr 3 (4) ("\to_R", 1);
+      nfr 4 (5, 8) ("\text{cut}", 1);
+        nfr 5 (6, 7) ("\wedge_R", 1);
+          nfr 6 () ("\gamma", 2);
+          nfr 7 () ("\delta", 1);
+        nfr 8 () ("\theta", 3);
+    nfr 9 () ("\upsilon", 2);
+draw drv_tree;
+endfig;
+
+
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+%
+% 3. Postamble
+%
+
+end
diff --git a/Master/texmf-dist/doc/metapost/drv/template/template.tex b/Master/texmf-dist/doc/metapost/drv/template/template.tex
new file mode 100644
index 00000000000..687c45778b3
--- /dev/null
+++ b/Master/texmf-dist/doc/metapost/drv/template/template.tex
@@ -0,0 +1,55 @@
+% Any piece of code related to font selection in the following preamble
+% (document class, font package, font selection commands ...) should be
+% reported in `template.mp'.
+
+\documentclass[twoside,11pt]{article}
+\usepackage[T1]{fontenc}
+\usepackage{amsmath}
+\usepackage{amssymb}
+
+% Choose your favourite fonts combination (if available).
+% See "http://ctan.tug.org/tex-archive/info/Free_Math_Font_Survey".
+%
+%\usepackage{cmbright}			% CM text & CM Bright math
+%\usepackage{ccfonts,eulervm}		% Concrete text & Euler math
+%\usepackage{ccfonts}			% Concrete text & math
+%\usepackage[math]{iwona}		% Iwona text & math
+%\usepackage[math]{kurier}		% Kurier text & math
+%\usepackage[math]{anttor}		% Antykwa Torunska text & math
+%\usepackage{kmath,kerkis}		% Kerkis text & math
+%\usepackage{fouriernc}			% New Century Schoolbook & Fourier math
+%\usepackage{pxfonts}			% Palatino & pxfonts math
+%\usepackage{mathpazo}			% Palatino & Pazo math
+%\usepackage{mathpple}			% Palatino & Euler math
+\usepackage[varg]{txfonts}		% Times & txfonts math
+%\usepackage{mathtime}			% Times & Belleek math
+%\usepackage{mathptmx}			% Times & Symbol math
+%\usepackage{mbtimes}			% Omega Serif text & Omega math
+%\usepackage{arev}			% Arev Sans text with Arev math
+%\usepackage[charter]{mathdesign}	% Bitstream Charter & Math Design math
+%\usepackage{comicsans}			% Comic Sans text & math
+%\usepackage[garamond]{mathdesign}	% Garamond & Math Design math
+%\usepackage{fourier}			% Utopia & Fourier math
+%\usepackage[utopia]{mathdesign}	% Utopia & Math Design math
+
+% Picture inclusion macro: \drv
+%
+% \drv includes a picture file in such a way that the baseline of the included
+% picture coincides with the baseline of the inclusion point. The code for \drv
+% was suggested by Josselin Noirel on the fr.comp.text.tex usenet group.
+
+\usepackage{graphicx}
+\makeatletter
+\def\Gin@def@bp#1\relax#2#3{\gdef#2{#3}}
+\newsavebox{\graphicsbox}
+\newcommand*{\drv}[1]{%
+\sbox{\graphicsbox}{\includegraphics{#1}}%
+\raisebox{\Gin@lly bp}%
+{\usebox{\graphicsbox}}}
+\makeatother
+
+\begin{document}
+\begin{gather*}
+\frac{\qquad}{}\drv{template.100}\frac{\qquad}{}
+\end{gather*}
+\end{document}