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%%
%% This is file `simplebnf.sty'.
%%
%% ---------------------------------------------------------------------------
%% The simplebnf package --- A simple package to format Backus-Naur form
%% Maintained by Jay Lee
%% E-mail: jaeho.lee@snu.ac.kr
%% Released under the MIT License.
%% ---------------------------------------------------------------------------
%%
\RequirePackage{expl3,xparse}
% mathtools is needed for the \Coloneqq simbol
\RequirePackage{mathtools}
\ProvidesExplPackage
{simplebnf}
{2023/01/07}
{0.3.2}
{A simple package to format Backus–Naur form}
\cs_generate_variant:Nn \regex_split:nnNTF {nVNTF}
\cs_generate_variant:Nn \regex_split:NnN {NVN}
\NewDocumentCommand\SimpleBNFDefEq{}{\ensuremath{\Coloneqq}}
\NewDocumentCommand\SimpleBNFDefOr{}{\ensuremath{|}}
\NewDocumentCommand\SimpleBNFStretch{}{0em}
\seq_new:N \l__input_seq
\seq_new:N \l__term_seq
\tl_new:N \l__term_tl
\tl_new:N \l__keypairs_tl
\tl_new:N \l__table_tl
\seq_new:N \l__keypairs_seq
\bool_new:N \l__first_rhs
\regex_new:N \g_simplebnf_rhs_newline_r
\regex_new:N \g_simplebnf_rhs_nb_r
%% Typeset a single rhs of a production.
%% \l__first_rhs = true => `::=' already typeset
%% \l__first_rhs = false => move to a newline and typeset `|'
%% #1 - rhs : annot or rhs
\cs_new:Nn \simplebnf_typeset_rhs:n
{
\bool_if:NTF \l__first_rhs
{
\bool_set_false:N \l__first_rhs
}
{
\tl_put_right:Nn \l__table_tl { \\ && \SimpleBNFDefOr & }
}
\tl_set:Nn \l_tmpa_tl { #1 }
\regex_replace_once:nnN { ^\s+ } {} \l_tmpa_tl
\regex_replace_once:nnN { \s+$ } {} \l_tmpa_tl
\regex_split:nVNTF { : } \l_tmpa_tl \l_tmpa_seq
{
\seq_pop_left:NNT \l_tmpa_seq \l_tmpa_tl
{
\regex_replace_all:NnN \g_simplebnf_rhs_nb_r { \c{SimpleBNFDefOr} } \l_tmpa_tl
% Expand only the local temporary variable.
\tl_put_right:No \l__table_tl
{
\exp_after:wN\bnfexpr\exp_after:wN{\l_tmpa_tl} &
}
}
\seq_pop_left:NNT \l_tmpa_seq \l_tmpb_tl
{
\regex_replace_once:nnN { ^\s+ } {} \l_tmpb_tl
\tl_put_right:No \l__table_tl
{
\exp_after:wN\bnfannot\exp_after:wN{\l_tmpb_tl}
}
}
}
{
\regex_replace_all:NnN \g_simplebnf_rhs_nb_r { \c{SimpleBNFDefOr} } \l_tmpa_tl
\tl_put_right:No \l__table_tl
{
\exp_after:wN\bnfexpr\exp_after:wN{\l_tmpa_tl}
}
}
}
%% Typeset a single lhs of a production.
%% #1 - lhs : either term or (term : annotation)
\cs_new:Nn \simplebnf_typeset_lhs:n
{
\tl_set:Nx \l_tmpa_tl { #1 }
\regex_replace_once:nnN { ^\s+ } {} \l_tmpa_tl
\regex_replace_once:nnN { \s+$ } {} \l_tmpa_tl
\regex_split:nVNTF { : } \l_tmpa_tl \l_tmpa_seq
{
\seq_pop_right:NN \l_tmpa_seq \l_tmpa_tl
\regex_replace_once:nnN { ^\s+ } {} \l_tmpa_tl
\tl_put_right:No \l__table_tl
{
\exp_after:wN\bnfannot\exp_after:wN{\l_tmpa_tl} &
}
\seq_pop_left:NN \l_tmpa_seq \l_tmpa_tl
\tl_put_right:No \l__table_tl
{
\exp_after:wN\bnfexpr\exp_after:wN{\l_tmpa_tl}
}
}
{
\tl_put_right:No \l__table_tl
{
\exp_after:wN&\exp_after:wN\bnfexpr\exp_after:wN{\l_tmpa_tl}
}
}
}
\NewDocumentCommand \bnfexpr { m } { \texttt { #1 } }
\NewDocumentCommand \bnfannot { m } { \textit{ #1 } }
%% Typeset a BNF grammar.
%% #1 - tabular specification (llcll)
%% #2 - regexp for newline separator for rhses
%% #2 - regexp for non-breaking separator for rhses
%% #3 - grammar
\NewDocumentEnvironment { bnfgrammar } { O{llcll} O{[^\|]\|[^\|]} O{\|\|} +b }
{
\regex_gset:Nn \g_simplebnf_rhs_newline_r { #2 }
\regex_gset:Nn \g_simplebnf_rhs_nb_r { #3 }
%% \l__input_seq is a list of term definitions.
\regex_split:nnN { ;; } { #4 } \l__input_seq
\begin{center}
\tl_set:Nn \l__table_tl
{
\begin{tabular}{#1}
}
\bool_set_true:N \l_tmp_first_term % Is this the first term in this grammar?
\seq_map_inline:Nn \l__input_seq
{
%% If not-first, add newline
\bool_if:NTF \l_tmp_first_term
{
\bool_set_false:N \l_tmp_first_term
}
{
\tl_put_right:Nn \l__table_tl { \\[\SimpleBNFStretch] }
}
\regex_split:nnNTF { ::= } { ##1 } \l__term_seq
% Parse a ::= definition
{
%% \l__term_seq - (lhs, rhses)...
%% \l__term_tl - lhs
%% \l__keypairs_tl - rhses
\seq_pop_left:NN \l__term_seq \l__term_tl
\seq_pop_left:NN \l__term_seq \l__keypairs_tl
\simplebnf_typeset_lhs:n{\l__term_tl}
\tl_put_right:Nn \l__table_tl
{
& \SimpleBNFDefEq &
}
%% \l__keypairs_seq - (rhs:annot | rhs)...
\regex_split:NVN \g_simplebnf_rhs_newline_r \l__keypairs_tl \l__keypairs_seq
\bool_set_true:N \l__first_rhs
\seq_map_function:NN \l__keypairs_seq \simplebnf_typeset_rhs:n
}
{
% Else, parse a \in declaration
\regex_split:nnNTF { \c{in} } { ##1 } \l__term_seq
{
%% \l__term_seq - (lhs, rhs)
\seq_pop_left:NN \l__term_seq \l_tmpa_tl
\simplebnf_typeset_lhs:n{\l_tmpa_tl}
\tl_put_right:Nn \l__table_tl
{
& $\in$ & $
}
\seq_pop_left:NN \l__term_seq \l_tmpa_tl
\tl_put_right:NV \l__table_tl \l_tmpa_tl
\tl_put_right:Nn \l__table_tl
{
$ &
}
}
{ \msg_error:nn {simplebnf} { Could not parser ##1 } }
}
}
\tl_put_right:Nn \l__table_tl { \end{tabular} }
\tl_use:N \l__table_tl
\end{center}
}
{ }
%% The MIT License (MIT)
%%
%% Copyright © 2019-2023 Jay Lee <jaeho.lee@snu.ac.kr>
%%
%% Permission is hereby granted, free of charge, to any person obtaining
%% a copy of this software and associated documentation files (the "Software"),
%% to deal in the Software without restriction, including without limitation
%% the rights to use, copy, modify, merge, publish, distribute, sublicense,
%% and/or sell copies of the Software, and to permit persons to whom the
%% Software is furnished to do so, subject to the following conditions:
%%
%% The above copyright notice and this permission notice shall be included
%% in all copies or substantial portions of the Software.
%%
%% THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
%% EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
%% OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
%% IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
%% DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
%% TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE
%% OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
%%
%% End of file `simplebnf.sty'.
|
