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%% $Id: xyidioms.doc,v 3.4 1997/05/18 01:14:25 krisrose Exp $
%%
%% Format-dependent idioms for Xy-pic.
%% Copyright (c) 1991-1997 Kristoffer H. Rose <krisrose@brics.dk>
%%
%% This file is part of the Xy-pic package for graphs and diagrams in TeX.
%% See the companion README and INSTALL files for further information.
%% Copyright (c) 1991-1997 Kristoffer H. Rose <krisrose@brics.dk>
%%
%% The Xy-pic package is free software; you can redistribute it and/or modify
%% it under the terms of the GNU General Public License as published by the
%% Free Software Foundation; either version 2 of the License, or (at your
%% option) any later version.
%%
%% The Xy-pic package is distributed in the hope that it will be useful, but
%% WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
%% or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
%% for more details.
%%
%% You should have received a copy of the GNU General Public License along
%% with this package; if not, write to the Free Software Foundation, Inc.,
%% 675 Mass Ave, Cambridge, MA 02139, USA.
%%
\ifx\xyidiomsloaded\empty \message{not reloaded}\endinput \fi
\let\xyidiomsloaded=\empty
\DOCMODE3%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
This included file provides some common ??w![idioms] whose definition
depends on the used format such that \Xy-pic can use predefined
??w![dimension registers] etc.\ and yet still be independent of the
format under which it is used. The current ??w![version]
(\stripRCS$Revision: 3.4 $) handles ??w![plain \TeX] (version 2
and 3~\cite{K84:TeXbook}), ??w![\AMS-\TeX] (version 2.0 and
2.1~\cite{S90:JoyT}), ??w![\LaTeX] (version 2.09~\cite{L86:LaTeX}
and~$2\varepsilon$~\cite{L94:LaTeX}), ??w![\AMS-\LaTeX] (version 1.0,
1.1~\cite{AMS91:AMS-LaTeX}, and~1.2), and eplain (version
2.6~\cite{B94:ExpandedPT})\footnote{The `v2' feature introduces some
name conflicts, in order to maintain compatibility with earlier
versions of \Xy-pic.\hfill}.
??w[system dependencies]??w[format dependencies]
\DOCMODE2%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
\paragraph*{Header:}
\DOCHEADER
\noindent
This is a separate file so that we can abort the definitions easily
using |\endinput|.
\paragraph*{Scratch registers:}
%
All the formats currently treated allow the use of the following
plain \TeX\ ??w![scratch register conventions]
(\cf~\cite[p.346]{K84:TeXbook})
%
\begin{itemize}
\item
|\count@| is available as a local scratch counter register.
\item
|\dimen@|, |\dimen@i|, |\dimen@ii|, |\dimen3| to |\dimen9|, and
|\dimen255| are available as scratch dimension registers.
\item
|\skip@|, |\skip1| to |\skip9|, and |\skip255| are available as
scratch skip registers.
\item
|\toks@| and |\toks1| to |\toks9| are available as scratch token
lists.
\item
|\boxz@| and |\box1| to |\box9| are available as scratch box
registers.
\end{itemize}
%
with the constraint that ??c![\global] should never (always)
be used when assigning to number 0, 2, 4, 6, 8, and 255 (1, 3, 5, 7,
and 9).
\paragraph*{\Xy-specific scratch registers:}
%
We first give new names to dimension registers 4, 6, and 8, since
none of the formats do that: |\A@|, |\B@|, and |\R@| are specific to
\Xy-pic and will be referred to as ??w![$A$], ??w![$B$], and
??w![$R$] in comments.
\DOCMODE(
\xywarnifdefined\A@ \dimendef\A@=4
\xywarnifdefined\B@ \dimendef\B@=6
\xywarnifdefined\R@ \dimendef\R@=8
\DOCMODE)
Some shared scratch registers are defined last.
\paragraph*{Idioms:}
%
First check that |\undefined| is indeed undefined\dots or rather: the
same as an extremely unlikely control sequence that we are making up:
\DOCMODE(
\ifx\undefined\AveryUNLIKELYc@ntr@lSEQUENCE@@\else
\errmessage{Xy-pic Error: \string\undefined\space defined.}\fi
\DOCMODE)
These idioms are so common they are just conditionally defined:
\DOCMODE(
\ifx\undefined\literal@ \def\literal@#1{#1}\fi
\ifx\undefined\eat@ \def\eat@#1{}\fi
\xydef@\xyFN@{\futurelet\next} % Now private because of AMS-LaTeX change.
\ifx\undefined\DN@ \def\DN@{\def\next@}\fi
\ifx\undefined\DNii@ \def\DNii@{\def\nextii@}\fi
\ifx\undefined\setboxz@h\def\setboxz@h{\setbox\z@\hbox}\fi
\ifx\undefined\wdz@ \def\wdz@{\wd\z@}\fi
\ifx\undefined\boxz@ \def\boxz@{\box\z@}\fi
\ifx\undefined\W@ \def\W@{\immediate\write16 }\fi
\ifx\undefined\space@ \def\space@.{\futurelet\space@\relax}\space@. \fi
\ifx\undefined\notempty \def\notempty#1{T\if @#1@F\else T\fi}\fi
\DOCMODE)
\paragraph*{Delayed setup:}
%
This is used when it is advantageous to delay loading of something
until after the preamble, \ie, after all options, \etc, have been
loaded. This is particularly true for nested ??c![\xywithoption]
uses that will otherwise be executed repeatedly. Currently properly
supported with \LaTeXe\ and the |amsppt| style of \AMS-\TeX.
\DOCMODE(
\xydef@\xysetup@dummy#1{\xyuncatcodes#1}
\xywarnifdefined\xysetup@@
\ifx\AtEndDocument\undefined
\expandafter\ifx\csname amsppt.sty\endcsname\relax
\let\xysetup@@=\xysetup@dummy
\else
\def\xysetup@@#1{%
\expandafter\def\expandafter\topmatter\expandafter{\topmatter
#1\xyuncatcodes}}\fi
\else
\def\xysetup@@#1{\AtBeginDocument{#1\xyuncatcodes}}
\fi
\ifx\xysetup@@\xysetup@dummy\else
\xysetup@@{\let\xysetup@@=\xysetup@dummy \xyuncatcodes}\fi
\DOCMODE)
Similarly, the following provides a place to insert `trailing
messages' if the format supports it; otherwise it just throws away
the argument (useful for repeating the most important warnings).
\DOCMODE(
\xywarnifdefined\xyclosedown@@
\ifx\AtEndDocument\undefined \let\xyclosedown@@=\eat@
\else \def\xyclosedown@@#1{\AtEndDocument{#1}}\fi
\DOCMODE)
This may be useful to hook into specialised mechanisms for including
|\special| material on the page.
\DOCMODE(
\xylet@\xy@begindvi=\literal@
\DOCMODE)
For example, \LaTeXe\ (post Dec~'94) defines an |\AtBeginDvi| macro
to allow zero-sized material to be placed at the beginning of each
shipped-out page. Among other uses, this allows such material not to
be discarded, when on a page containing only floats. This is used by
\Xy-pic in connection with the \PS\ header dictionary |xyps-ps.doc|.
\DOCMODE(
\ifx\undefined\AtBeginDvi\else
\AtBeginDocument{\let\xy@begindvi=\AtBeginDvi}
\AtBeginDvi{\global\let\xy@begindvi=\literal@}\fi
\DOCMODE)
\paragraph*{Shared scratch registers:}
%
Everything else in this file is also done by \AMS-\TeX\ so we exit
here when using that format after renaming their |\toks@@| to
|\toks@ii|\dots
\DOCMODE(
\ifx\amstexloaded@\relax
\xylet@\toks@ii=\toks@@ \endinput \fi
\DOCMODE)
Thus the job of allocating scratch registers is simple except for
counters where we only have one so we use \LaTeX\ scratch counters
when available and otherwise allocate two new ones:
\DOCMODE(
\ifx\@tempcnta\undefined
\xynew@{count}\count@@
\xynew@{count}\count@@@
\else
\xylet@\count@@=\@tempcnta
\xylet@\count@@@=\@tempcntb
\fi
\DOCMODE)
Finally the second scratch token register not available with \LaTeX.
\DOCMODE(
\ifx\undefined\toks@ii \toksdef\toks@ii=2 \fi
\DOCMODE)
\paragraph*{End \& log:}
%
That's all.
\DOCMODE(
\endinput
% $Log: xyidioms.doc,v $
% Revision 3.4 1997/05/18 01:14:25 krisrose
% Essential bugfixes.
%
% Revision 3.3 1996/12/19 03:31:56 krisrose
% Maintenance release
%
% Revision 3.1 1995/09/05 20:31:32 kris
% Releasing!
%
% Revision 3.0 1995/07/07 20:14:21 kris
% Major release w/new User's Guide!
%
% Revision 2.13 1995/07/04 15:11:17 kris
% Ready to release v3?
%
% Revision 2.12 1994/10/25 11:34:25 kris
% Interim release just before v3 [works with AMS-LaTeX 1.2]...
%
% Revision 2.11 1994/07/05 10:37:32 kris
% Third 3beta release [bug fixes].
% Experimental graph feature included (for ECCT-94 presentation).
%
% Revision 2.9 1994/06/09 15:02:49 kris
% Release 3beta.
%
% Revision 2.8 1994/04/08 04:30:00 kris
% Second (bug fix) 3alpha release.
%
% Revision 2.7 1994/03/08 02:06:01 kris
% Release 3alpha.
%
% Revision 2.6.9.1 1994/03/07 04:22:46 kris
% Last internal 3alpha and pre-2.7 release.
%
% Now contains scratch register allocations.
% Cleaned of AMS-TeX special macros.
% Renamed from xyamstex.doc to xyidioms.doc for version 2.7.
%
% Revision 2.4 1992/01/22 02:15:10 kris
% \\ works with AMS-LaTeX: don't use \Let@ [Werner Struckmann/Darrel Hankerson]
% Made redefinition of \text conditional.
%
% Revision 2.3 1992/01/10 21:43:09 kris
% Fixed AMS-LaTeX name clash problems.
%
% Revision 2.2 1992/01/09 04:05:40 kris
% Patched to fix problem with \text and support AMS-LaTeX.
%
% Revision 2.1 1992/01/02 14:55:27 kris
% Release version.
%
% Revision 1.3 1991/12/17 04:51:16 kris
% Version distributed with `final draft' on Usenet.
\DOCMODE)
\DOCMODE3%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% Tell Emacs that this is a LaTeX document and how it is formatted:
% Local Variables:
% mode:latex
% fill-prefix:"\t"
% fill-column:77
% paragraph-separate:"^[ \t\f]*$\\|^[^\t]\\|\\\\\\\\\\|\\$\\$\\|[^\n\\\\][%&]"
% paragraph-start:"^[ \t\f]*$\\|^[^\t]\\|\\\\\\\\\\|\\$\\$\\|[^\n\\\\][%&]"
% End:
|
