% The ebproof package - Formal proofs in the style of sequent calculus %% ebproof.sty %% Copyright 2017 Emmanuel Beffara % 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 Emmanuel Beffara. % This work consists of the files ebproof.sty and ebproof.tex. \NeedsTeXFormat{LaTeX2e} \RequirePackage{expl3} \RequirePackage{xparse} \ProvidesExplPackage{ebproof}{2017/05/17}{2.0}{EB's proof trees} %% Parameters %%% Declaration of the parameters \keys_define:nn { ebproof } { % general shape center .bool_set:N = \l_ebproof_center_bool, proof~style .choice: , proof~style / upwards .code:n = \bool_set_false:N \l_ebproof_updown_bool, proof~style / downwards .code:n = \bool_set_true:N \l_ebproof_updown_bool, % spacing separation .dim_set:N = \l_ebproof_separation_dim, rule~margin .dim_set:N = \l_ebproof_rule_margin_dim, % shape of inference lines rule~thickness .dim_set:N = \l_ebproof_rule_thickness_dim, rule~separation .dim_set:N = \l_ebproof_rule_separation_dim, rule~dash~length .dim_set:N = \l_ebproof_rule_dash_length_dim, rule~dash~space .dim_set:N = \l_ebproof_rule_dash_space_dim, rule~code .tl_set:N = \l_ebproof_rule_code_tl, rule~style .choice:, % templates template .tl_set:N = \l_ebproof_template_tl, left~template .tl_set:N = \l_ebproof_left_template_tl, right~template .tl_set:N = \l_ebproof_right_template_tl, % labels left~label .tl_set:N = \l_ebproof_left_label_tl, right~label .tl_set:N = \l_ebproof_right_label_tl, left~label~template .tl_set:N = \l_ebproof_left_label_template_tl, right~label~template .tl_set:N = \l_ebproof_right_label_template_tl, label~separation .dim_set:N = \l_ebproof_label_separation_dim, label~axis .dim_set:N = \l_ebproof_label_axis_dim, } %%% Rule styles \NewDocumentCommand \ebproofnewrulestyle { mm } { \keys_define:nn { ebproof } { rule~style / #1 .meta:nn = { ebproof } { #2 } } } \ebproofnewrulestyle { simple } { rule~code = { \tex_hrule:D height \l_ebproof_rule_thickness_dim } } \ebproofnewrulestyle { no~rule } { rule~code = } \ebproofnewrulestyle { double } { rule~code = { \tex_hrule:D height \l_ebproof_rule_thickness_dim \skip_vertical:N \l_ebproof_rule_separation_dim \tex_hrule:D height \l_ebproof_rule_thickness_dim } } \ebproofnewrulestyle { dashed } { rule~code = { \hbox_to_wd:nn { \tex_hsize:D } { \dim_set:Nn \l_tmpa_dim { \l_ebproof_rule_dash_space_dim / 2 } \skip_horizontal:n { -\l_tmpa_dim } \tex_cleaders:D \hbox:n { \skip_horizontal:N \l_tmpa_dim \tex_vrule:D height \l_ebproof_rule_thickness_dim width \l_ebproof_rule_dash_length_dim \skip_horizontal:N \l_tmpa_dim }\tex_hfill:D \skip_horizontal:n { -\l_tmpa_dim } } } } %%% Default values \keys_set:nn { ebproof } { center = true, proof~style = upwards, separation = 1.5em, rule~margin = .7ex, rule~thickness = .4pt, rule~separation = 2pt, rule~dash~length = .2em, rule~dash~space = .3em, rule~style = simple, template = $\inserttext$, left~template = $\inserttext\mathrel{}$, right~template = $\mathrel{}\inserttext$, left~label = , right~label = , left~label~template = \inserttext, right~label~template = \inserttext, label~separation = 0.5em, label~axis = 0.5ex } %%% Defining style macros \NewDocumentCommand \ebproofnewstyle { mm } { \keys_define:nn { ebproof } { #1 .meta:n = { #2 } } } %% Proof trees % Proof trees are represented as a data structure that consists of a box and a % set of marks, which are vertical positions in the box (as distances from the % left edge). Arbitrary marks can be defined, the folowing are used for % alignment: % - left : the left of the conclusion % - right : the right of the conclusion % - axis : the vertical axis of the conclusion %%% Registers % TeX does not actually provide data structures, so we have to encode things. % We provide an allocator for "registers" holding boxes with attributes. Such % a register consists in a box register and a property list for marks, which % maps mark names to values as explicit dimensions with units. % Create a new register. \cs_new:Nn \ebproof_new:N { \box_new:N #1 \prop_new:c { l_ebproof_marks_ \__int_value:w #1 _prop } } % Clear a register. \cs_new:Nn \ebproof_clear:N { \hbox_set:Nn #1 {} % Using \box_clear:N instead would not work because trying to push this box % on the stack would not actually append any box. \prop_clear:c { l_ebproof_marks_ \__int_value:w #1 _prop } \ebproof_set_mark:Nnn #1 { left } { 0pt } \ebproof_set_mark:Nnn #1 { right } { 0pt } \ebproof_set_mark:Nnn #1 { axis } { 0pt } } %%% Mark operations % Set the value of a mark. The third argument is a dimension expression. \dim_new:N \l_ebproof_transit_dim \cs_new:Nn \ebproof_set_mark:Nnn { \dim_set:Nn \l_ebproof_transit_dim { #3 } \prop_put:cnV { l_ebproof_marks_ \__int_value:w #1 _prop } { #2 } \l_ebproof_transit_dim } % Get the value of a mark. This is expandable and can be used in expressions. \cs_new:Nn \ebproof_mark:Nn { \prop_item:cn { l_ebproof_marks_ \__int_value:w #1 _prop } { #2 } } % Shift the marks by a specified amount, without modifying the box. \cs_new:Nn \ebproof_shift_x:Nn { \prop_map_inline:cn { l_ebproof_marks_ \__int_value:w #1 _prop } { \ebproof_set_mark:Nnn #1 { ##1 } { ##2 + #2 } } } % Move the left and right marks of the first tree so that they are at least as % far from the axis as they are in the second tree. For instance if the marks % are set as % 1: L---A-------R % 2: L-------A---R % then the marks of the first tree are then set as % 1: L-------A-------R % The contents of the tree are unchanged. \cs_new:Nn \ebproof_enlarge_conclusion:NN { \dim_set:Nn \l_tmpa_dim { \ebproof_mark:Nn #1 {axis} + \ebproof_mark:Nn #2 {left} - \ebproof_mark:Nn #2 {axis} } \dim_compare:nNnT { \l_tmpa_dim } < { \ebproof_mark:Nn #1 {left} } { \ebproof_set_mark:Nnn #1 {left} { \l_tmpa_dim } } \dim_set:Nn \l_tmpa_dim { \ebproof_mark:Nn #1 {axis} + \ebproof_mark:Nn #2 {right} - \ebproof_mark:Nn #2 {axis} } \dim_compare:nNnT { \l_tmpa_dim } > { \ebproof_mark:Nn #1 {right} } { \ebproof_set_mark:Nnn #1 {right} { \l_tmpa_dim } } } %%% Building blocks % Make a tree with explicit material in horizontal mode. Set the left and % right marks to extremal positions and set the axis in the middle. \cs_new:Nn \ebproof_make_simple:Nn { \hbox_set:Nn #1 { #2 } \ebproof_set_mark:Nnn #1 { left } { 0pt } \ebproof_set_mark:Nnn #1 { axis } { \box_wd:N #1 / 2 } \ebproof_set_mark:Nnn #1 { right } { \box_wd:N #1 } } % Make a tree with explicit material in horizontal mode, split in two parts. % Set the left and right marks to extremal positions and set the axis between % the two parts. \cs_new:Nn \ebproof_make_split:Nnn { \ebproof_set_mark:Nnn #1 { left } { 0pt } \hbox_set:Nn #1 { #2 } \ebproof_set_mark:Nnn #1 { axis } { \box_wd:N #1 } \hbox_set:Nn #1 { \hbox_unpack:N #1 #3 } \ebproof_set_mark:Nnn #1 { right } { \box_wd:N #1 } } % Make a tree with explicit material in vertical mode, using an explicit width % and axis. \cs_new:Nn \ebproof_make_vertical:Nnnn { \ebproof_set_mark:Nnn #1 { left } { 0pt } \ebproof_set_mark:Nnn #1 { axis } { #2 } \ebproof_set_mark:Nnn #1 { right } { #3 } \vbox_set:Nn #1 { \dim_set:Nn \tex_hsize:D { \ebproof_mark:Nn #1 {right} } #4 } \box_set_wd:Nn #1 { \ebproof_mark:Nn #1 {right} } } %%% Assembling boxes % Extend a tree box. The marks are shifted so that alignment is preserved. The % arguments are dimensions for the left, top, right and bottom sides % respectively. \cs_new:Nn \ebproof_extend:Nnnnn { \dim_compare:nNnF { #2 } = { 0pt } { \hbox_set:Nn #1 { \skip_horizontal:n { #2 } \box_use:N #1 } \ebproof_shift_x:Nn #1 { #2 } } \box_set_ht:Nn #1 { \box_ht:N #1 + #3 } \box_set_wd:Nn #1 { \box_wd:N #1 + #4 } \box_set_dp:Nn #1 { \box_dp:N #1 + #5 } } % Append the contents of the second tree to the first one on the right, with % matching baselines. The marks of both trees are preserved. The middle % argument specifies the space to insert between boxes. \cs_new:Nn \ebproof_append_right:NnN { \hbox_set:Nn #1 { \box_use:N #1 \dim_compare:nNnF { #2 } = { 0pt } { \skip_horizontal:n { #2 } } \box_use:N #3 } } % Append the contents of the second tree to the first one on the left, with % matching baselines. The marks of the first tree are shifted accordingly. The % middle argument specifies the space to insert between boxes. \cs_new:Nn \ebproof_append_left:NnN { \ebproof_shift_x:Nn #1 { \box_wd:N #3 + #2 } \hbox_set:Nn #1 { \box_use:N #3 \dim_compare:nNnF { #2 } = { 0pt } { \skip_horizontal:n { #2 } } \box_use:N #1 } } % Shift of two trees to the right so that the axes match. The marks of the one % that is shifted are updated accordingly. \cs_new:Nn \ebproof_align:NN { \dim_set:Nn \l_tmpa_dim { \ebproof_mark:Nn #2 {axis} - \ebproof_mark:Nn #1 {axis} } \dim_compare:nNnTF \l_tmpa_dim < { 0pt } { \ebproof_extend:Nnnnn #2 { -\l_tmpa_dim } { 0pt } { 0pt } { 0pt } } { \ebproof_extend:Nnnnn #1 { \l_tmpa_dim } { 0pt } { 0pt } { 0pt } } } % Append the contents of the second tree above the first one, with matching % axes. The marks of the first tree are preserved. \cs_new:Nn \ebproof_append_above:NN { \ebproof_align:NN #1 #2 \vbox_set:Nn #1 { \box_use:N #2 \tex_prevdepth:D -1000pt \box_use:N #1 } } % Append the contents of the second tree below the first one, with matching % axes. The marks of the first tree are preserved. \cs_new:Nn \ebproof_append_below:NN { \ebproof_align:NN #1 #2 \vbox_set_top:Nn #1 { \box_use:N #1 \tex_prevdepth:D -1000pt \box_use:N #2 } } % Shift the material in a tree vertically so that the height and depth are % equal (like TeX's \vcenter but around the baseline). \cs_new:Nn \ebproof_vcenter:N { \dim_set:Nn \l_tmpa_dim { ( \box_ht:N #1 - \box_dp:N #1 ) / 2 } \box_set_eq:NN \l_tmpa_box #1 \hbox_set:Nn #1 { \box_move_down:nn { \l_tmpa_dim } { \box_use:N \l_tmpa_box } } } %% Making inferences % % The following commands use the parameters defined at the beginning of the % package for actually building proof trees using the commands defined above. % Append the contents of the second tree above or below the first one, % depending on current settings. Axes are aligned and the marks of the first % tree are preserved. \cs_new:Nn \ebproof_append_vertical:NN { \bool_if:NTF \l_ebproof_updown_bool { \ebproof_append_below:NN #1 #2 } { \ebproof_append_above:NN #1 #2 } } % Make a box containing an inference rule with labels, using the current % settings. The width and axis position are taken as those of the conclusion % of another tree box. The third argument is used as a temporary register for % building labels. \cs_new:Nn \ebproof_make_rule_for:NNN { % Build the rule. \ebproof_make_vertical:Nnnn #1 { \ebproof_mark:Nn #2 {axis} - \ebproof_mark:Nn #2 {left} } { \ebproof_mark:Nn #2 {right} - \ebproof_mark:Nn #2 {left} } { \skip_vertical:N \l_ebproof_rule_margin_dim \tl_if_empty:NF { \l_ebproof_rule_code_tl } { \tl_use:N \l_ebproof_rule_code_tl \skip_vertical:N \l_ebproof_rule_margin_dim } } \ebproof_vcenter:N #1 % Append the left label \tl_if_blank:VF \l_ebproof_left_label_tl { \ebproof_make_simple:Nn #3 { \box_move_down:nn { \l_ebproof_label_axis_dim } { \hbox:n { \cs_set_eq:NN \inserttext \l_ebproof_left_label_tl \tl_use:N \l_ebproof_left_label_template_tl } } } \box_set_ht:Nn #3 { 0pt } \box_set_dp:Nn #3 { 0pt } \ebproof_append_left:NnN \l_ebproof_c_box \l_ebproof_label_separation_dim \l_ebproof_d_box } % Append the right label \tl_if_blank:VF \l_ebproof_right_label_tl { \ebproof_make_simple:Nn #3 { \box_move_down:nn { \l_ebproof_label_axis_dim } { \hbox:n { \cs_set_eq:NN \inserttext \l_ebproof_right_label_tl \tl_use:N \l_ebproof_right_label_template_tl } } } \box_set_ht:Nn #3 { 0pt } \box_set_dp:Nn #3 { 0pt } \ebproof_append_right:NnN \l_ebproof_c_box \l_ebproof_label_separation_dim \l_ebproof_d_box } } %% Stack-based interface %%% The stack % Logically, box structures are stored on a stack. However, TeX does not % provide data structures for that and the grouping mechanism is not flexible % enough, so we encode them using what we actually have. A stack for boxes is % implemented using a global hbox |\g_ebproof_stack_box| that contains all the % boxes successively. A sequence |\g_ebproof_stack_seq| is used to store the % dimensions property lists textually. We maintain a counter % |\g_ebproof_level_int| with the number of elements on the stack, for % consistency checks. \int_new:N \g_ebproof_level_int \box_new:N \g_ebproof_stack_box \seq_new:N \g_ebproof_stack_seq % Clear the stack. \cs_new:Nn \ebproof_clear_stack: { \int_gset:Nn \g_ebproof_level_int { 0 } \hbox_gset:Nn \g_ebproof_stack_box { } \seq_gclear:N \g_ebproof_stack_seq } % Push the contents of a register on the stack. \cs_new:Nn \ebproof_push:N { \int_gincr:N \g_ebproof_level_int \hbox_gset:Nn \g_ebproof_stack_box { \hbox_unpack:N \g_ebproof_stack_box \box_use:N #1 } \seq_gput_left:Nv \g_ebproof_stack_seq { l_ebproof_marks_ \__int_value:w #1 _prop } } % Pop the value from the top of the stack into a register. \cs_new:Nn \ebproof_pop:N { \int_compare:nNnTF { \g_ebproof_level_int } > { 0 } { \int_gdecr:N \g_ebproof_level_int \hbox_gset:Nn \g_ebproof_stack_box { \hbox_unpack:N \g_ebproof_stack_box \box_gset_to_last:N \g_tmpa_box } \box_set_eq_clear:NN #1 \g_tmpa_box \seq_gpop_left:NN \g_ebproof_stack_seq \l_tmpa_tl \tl_set_eq:cN { l_ebproof_marks_ \__int_value:w #1 _prop } \l_tmpa_tl } { \PackageError{ebproof}{Missing~premiss~in~a~proof~tree}{} \ebproof_clear:N #1 } } %%% Assembling trees \ebproof_new:N \l_ebproof_a_box \ebproof_new:N \l_ebproof_b_box \ebproof_new:N \l_ebproof_c_box \ebproof_new:N \l_ebproof_d_box % Join horizontally a number of elements at the top of the stack. If several % trees are joined, use the left mark of the left tree, the right mark of the % right tree and set the axis in the middle of these marks. \cs_new:Nn \ebproof_join_horizontal:n { \int_case:nnF { #1 } { { 0 } { \group_begin: \ebproof_clear:N \l_ebproof_a_box \ebproof_push:N \l_ebproof_a_box \group_end: } { 1 } { } } { \group_begin: \ebproof_pop:N \l_ebproof_a_box \prg_replicate:nn { #1 - 1 } { \ebproof_pop:N \l_ebproof_b_box \ebproof_append_left:NnN \l_ebproof_a_box \l_ebproof_separation_dim \l_ebproof_b_box } \ebproof_set_mark:Nnn \l_ebproof_a_box { left } { \ebproof_mark:Nn \l_ebproof_b_box { left } } \ebproof_set_mark:Nnn \l_ebproof_a_box { axis } { ( \ebproof_mark:Nn \l_ebproof_a_box { left } + \ebproof_mark:Nn \l_ebproof_a_box { right } ) / 2 } \ebproof_push:N \l_ebproof_a_box \group_end: } } % Join vertically the two elements at the top of the stack, with a horizontal % rule of the appropriate size. \cs_new:Nn \ebproof_join_vertical: { \group_begin: \ebproof_pop:N \l_ebproof_a_box \ebproof_pop:N \l_ebproof_b_box \ebproof_enlarge_conclusion:NN \l_ebproof_b_box \l_ebproof_a_box \ebproof_make_rule_for:NNN \l_ebproof_c_box \l_ebproof_b_box \l_ebproof_d_box \ebproof_append_vertical:NN \l_ebproof_a_box \l_ebproof_c_box \ebproof_append_vertical:NN \l_ebproof_a_box \l_ebproof_b_box \ebproof_push:N \l_ebproof_a_box \group_end: } %%% High-level commands % Push a box with default formatting, using explicit alignment if the code % contains a |&| character \cs_new:Npn \ebproof_statement_parse:w #1\ebproof_statement_stop: { \tl_if_empty:nTF { #3 } { \ebproof_make_simple:Nn \l_ebproof_a_box { \cs_set:Npn \inserttext { #1 } \tl_use:N \l_ebproof_template_tl } } { \ebproof_make_split:Nnn \l_ebproof_a_box { \cs_set:Npn \inserttext { #1 } \tl_use:N \l_ebproof_left_template_tl } { \cs_set:Npn \inserttext { #2 } \tl_use:N \l_ebproof_right_template_tl } } \ebproof_push:N \l_ebproof_a_box } \cs_new:Nn \ebproof_push_statement:n { \ebproof_statement_parse:w #1&& \ebproof_statement_stop: } %% Document interface %%% Functions to define statements % The |\g_ebproof_stack_seq| variable contains the list of all defined % statements. For each statement |X|, there is a document command |\ebproofX| % and the alias |\X| is defined when entering a |prooftree| environment. \seq_new:N \g_ebproof_statements_seq % Install the aliases for statements, saving the original value of the control % sequences. \cs_new:Nn \ebproof_setup_statements: { \seq_map_inline:Nn \g_ebproof_statements_seq { \cs_set_eq:cc { ebproof_saved_ ##1 } { ##1 } \cs_set_eq:cc { ##1 } { ebproof ##1 } } } % Restore the saved meanings of the control sequences. This is useful when % interpreting user-provided code in statement arguments. The meanings are % automatically restored when leaving a |prooftree| environment because of % grouping. \cs_new:Nn \ebproof_restore_statements: { \seq_map_inline:Nn \g_ebproof_statements_seq { \cs_set_eq:cc { ##1 } { ebproof_saved_ ##1 } } } % Define a new statement. The first argument is the name, the second one is an % argument specifier as used by |xparse| and the third one is the body of the % command. \cs_new:Nn \ebproof_new_statement:nnn { \exp_args:Nc \NewDocumentCommand { ebproof#1 }{ #2 } { #3 } \seq_put_right:Nn \g_ebproof_statements_seq { #1 } } % Define a deprecated statement. The syntax is the same as above except that % an extra argument in third position indicates what should be used instead. % The effect is the same except that a warning message is issued the first % time the statement is used. \cs_new:Nn \ebproof_new_deprecated_statement:nnnn { \cs_new:cpn { ebproof_#1_warning: } { \PackageWarning { ebproof } { \token_to_str:c{#1}~is~deprecated,~#3 } \cs_gset:cn { ebproof_#1_warning: } { } } \ebproof_new_statement:nnn { #1 } { #2 } { \use:c { ebproof_#1_warning: } #4 } } %%% Basic commands \ebproof_new_statement:nnn { set } { m } { \keys_set:nn { ebproof } { #1 } } \ebproof_new_statement:nnn { hypo } { O{} m } { \group_begin: \ebproof_restore_statements: \keys_set:nn { ebproof } { #1 } \ebproof_push_statement:n { #2 } \group_end: } \ebproof_new_statement:nnn { infer } { O{} m O{} m } { \group_begin: \ebproof_restore_statements: \keys_set_known:nnN { ebproof / rule~style } { #1 } \l_tmpa_tl \keys_set:nV { ebproof } \l_tmpa_tl \tl_set:Nn \l_ebproof_right_label_tl { #3 } \ebproof_join_horizontal:n { #2 } \ebproof_push_statement:n { #4 } \ebproof_join_vertical: \group_end: } \ebproof_new_statement:nnn { ellipsis } { m m } { \group_begin: \ebproof_restore_statements: \tl_clear:N \l_ebproof_rule_code_tl \ebproof_make_split:Nnn \l_ebproof_a_box { } { \vbox_set:Nn \l_tmpa_box { \skip_vertical:n { 1.2ex } \hbox:n { \tex_ignorespaces:D #1 } \skip_vertical:n { 1.2ex } } \vbox_to_ht:nn { \box_ht:N \l_tmpa_box } { \tex_xleaders:D \vbox_to_ht:nn { .8ex } { \tex_vss:D \hbox:n { . } \tex_vss:D } \tex_vfill:D } \hbox_overlap_right:n { ~ \box_use:N \l_tmpa_box } } \ebproof_push:N \l_ebproof_a_box \ebproof_join_vertical: \ebproof_push_statement:n {#2} \ebproof_join_vertical: \group_end: } %%% Modifying trees % Rewrite the box at the top of the stack while preserving its dimensions an % marks. The code is typeset in horizontal mode, with control sequences to % access the original box and its marks: % - \treebox is a box register with the original material % - \treemark{NAME} provides the value of a given mark \ebproof_new_statement:nnn { rewrite } { m } { \group_begin: \ebproof_restore_statements: \ebproof_pop:N \l_ebproof_a_box \box_set_eq:NN \l_tmpa_box \l_ebproof_a_box \hbox_set:Nn \l_tmpb_box { \cs_set_eq:NN \treebox \l_tmpa_box \cs_set:Npn \treemark { \ebproof_mark:Nn \l_ebproof_a_box } { #1 } } \box_set_wd:Nn \l_tmpb_box { \box_wd:N \l_ebproof_a_box } \box_set_ht:Nn \l_tmpb_box { \box_ht:N \l_ebproof_a_box } \box_set_dp:Nn \l_tmpb_box { \box_dp:N \l_ebproof_a_box } \box_set_eq:NN \l_ebproof_a_box \l_tmpb_box \ebproof_push:N \l_ebproof_a_box \group_end: } % Insert |\left| and |\right| delimiters without changing the alignment \ebproof_new_statement:nnn { delims } { m m } { \group_begin: \ebproof_restore_statements: \ebproof_pop:N \l_ebproof_a_box \hbox_set:Nn \l_tmpa_box { $ \tex_vcenter:D { \box_use:N \l_ebproof_a_box } $ } \dim_set:Nn \l_tmpa_dim { \box_ht:N \l_tmpa_box - \box_ht:N \l_ebproof_a_box } \hbox_set:Nn \l_ebproof_a_box { $ #1 \tex_vrule:D height \box_ht:N \l_tmpa_box depth \box_dp:N \l_tmpa_box width 0pt \tex_right:D . $ } \ebproof_shift_x:Nn \l_ebproof_a_box { \box_wd:N \l_ebproof_a_box } \hbox_set:Nn \l_ebproof_a_box { \hbox_unpack:N \l_ebproof_a_box $ \tex_left:D . \box_use:N \l_tmpa_box #2 $ } \hbox_set:Nn \l_ebproof_a_box { \box_move_down:nn { \l_tmpa_dim } { \box_use:N \l_ebproof_a_box } } \ebproof_push:N \l_ebproof_a_box \group_end: } %%% Deprecated statements % These statements were defined in versions 1.x of the package, they are % preserved for temporary upwards compatibility and will be removed in a % future version. \ebproof_new_deprecated_statement:nnnn { Alter } { m } { use~\token_to_str:c{rewrite}~instead } { \ebproofrewrite{ #1 \box\treebox } } \ebproof_new_deprecated_statement:nnnn { Delims } { } { use~\token_to_str:c{delims}~instead } { \ebproofdelims } \ebproof_new_deprecated_statement:nnnn { Ellipsis } { } { use~\token_to_str:c{ellipsis}~instead } { \ebproofellipsis } \ebproof_new_deprecated_statement:nnnn { Hypo } { } { use~\token_to_str:c{hypo}~instead } { \ebproofhypo } \ebproof_new_deprecated_statement:nnnn { Infer } { } { use~\token_to_str:c{infer}~instead } { \ebproofinfer } %%% Environment interface \ebproof_clear_stack: \tl_new:N \l_ebproof_start_level_tl \NewDocumentEnvironment { prooftree } { s O{} } { \keys_set_known:nnN { ebproof / proof~style } { #2 } \l_tmpa_tl \keys_set:nV { ebproof } \l_tmpa_tl \tl_set:Nx \l_ebproof_start_level_tl { \int_use:N \g_ebproof_level_int } \vbox_set:Nw \l_tmpa_box \ebproof_setup_statements: } { \vbox_set_end: \ebproof_pop:N \l_ebproof_a_box \int_compare:nNnF { \g_ebproof_level_int } = { \tl_use:N \l_ebproof_start_level_tl } { \PackageError{ebproof}{Malformed~proof~tree}{ Some~hypotheses~were~declared~but~not~used~in~this~tree.} } \IfBooleanTF { #1 } { \[ \box_use:N \l_ebproof_a_box \] \ignorespacesafterend } { \hbox_unpack:N \c_empty_box \bool_if:NTF \l_ebproof_center_bool { \hbox:n { $ \tex_vcenter:D { \box_use:N \l_ebproof_a_box } $ } } { \box_use:N \l_ebproof_a_box } } } % A trick for the starred version: \cs_new:cpn { prooftree* } { \prooftree* } \cs_new:cpn { endprooftree* } { \endprooftree }