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%%% LaTeX2e package file to set EBNF in the style of the Haskell report
%%%
%%% Manuel M. T. Chakravarty <chak@cse.unsw.edu.au> [1997..2001]
%%%
%%% $Id: grammar.sty,v 1.1 2003/01/14 06:58:33 chak Exp $
%%%
%%% This file 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.
%%%
%%% This file 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.
%%%
%%% DOCU ======================================================================
%%%
%%% As a cheap (and ineffective) substitute for proper documentation, here an
%%% example using the macros:
%%%
%%% \begin{grammar}
%%% \grule{ftype}{%
%%% \gnterm{frtype}}
%%% \gor{%
%%% \gnterm{fatype} -> \gnterm{ftype}}
%%% \grule{frtype}{%
%%% \gnterm{fatype}}
%%% \gor{%
%%% ()}
%%% \grule[$k\geq0$]{fatype}{%
%%% \gnterm{qtycon} \gnterm[1]{atype} \gellipse\ \gnterm[k]{atype}}
%%% \end{grammar}
%%%
%%% TODO ======================================================================
%%%
%%% * flexible way of determining the column width is needed (should be the
%%% same throughout a single grammar (or even the whole document)
%%%
\ProvidesPackage{grammar}[2001/04/17, v0.5a, <chak@cse.unsw.edu.au>]
\RequirePackage{ifthen}
% font configuration
%
% * these two commands can be redefined to change the default fonts for
% terminals and non-terminals, respectively
%
\newcommand{\gtermfont}{\ttfamily}
\newcommand{\gntermfont}{\rmfamily\itshape}
% remembers whether we are in the star form of the grammar environment
% (internal)
%
\newif\if@quoted
% grammar environment
%
% * typeset in paragraph mode within a tabular
% * there are four columns, containing the nonterminal, rule symbol (-> or |),
% the rules rhs, and a comment, respectively
% * the star form of the command is not `quote'd
%
\newenvironment{grammar}{%
\@quotedtrue
\@grammar
}{%
\@endgrammar
}
\newenvironment{grammar*}{%
\@quotedfalse
\@grammar
}{%
\@endgrammar
}
% internal implementation of the grammar environment
%
\newcommand{\@grammar}{%
\gtermfont % for terminals
\if@quoted\quote\fi
\tabular{@{}lcl@{\quad}l@{}}
}
\newcommand{\@endgrammar}{%
\endtabular
\if@quoted\endquote\fi
\ignorespaces\global\@ignoretrue
}
% a rule: optional comment, lhs, and rhs
%
\newcommand{\grule}[3][!*NEVER USED ARGUMENT*!]{%
\ifthenelse{\equal{#1}{!*NEVER USED ARGUMENT*!}}{%
\gnterm{#2} &$\rightarrow$& #3 \\
}{%
\gnterm{#2} &$\rightarrow$& #3 & \rmfamily(#1)\\
}%
}
% a rule alternative: optional comment and rhs
%
\newcommand{\gor}[2][!*NEVER USED ARGUMENT*!]{%
\ifthenelse{\equal{#1}{!*NEVER USED ARGUMENT*!}}{%
&$|$& #2\\
}{%
&$|$& #2 & \rmfamily(#1)\\
}%
}
% set a non-terminal with an optimal subscript
%
\newcommand{\gnterm}[2][!*NEVER USED ARGUMENT*!]{%
\bgroup
\gntermfont#2%
\ifthenelse{\equal{#1}{!*NEVER USED ARGUMENT*!}}\relax{%
\(_{#1}\)%
}%
\egroup
}
\newcommand{\galt}{$|$} % inline alternatives
\newcommand{\gellipse}{\textrm{\ldots}} % ellipses
\newcommand{\ggroup}[1]{\textrm(#1\textrm)} % grouped expression
\newcommand{\gopt}[1]{\textrm[#1\textrm]} % optinal term
\newcommand{\grepeat}[1]{\textrm\{#1\textrm\}} % repeated term
\newcommand{\gminus}[1]{% % set difference
\(_{\langle\mbox{\scriptsize #1}\rangle}\)}
\newcommand{\gverbal}[1]{{\rmfamily\textbf{#1}}}% informal description
% the following command is for terminals, but it is not necessary with the
% `grammar' environment, as terminals are the default; it is however useful in
% the rest of the text
%
\newcommand{\gterm}[1]{{\normalfont\gtermfont#1}}
% some characters that are difficult to denote
%
\newcommand{\gbackslash}{\char"5C}
\newcommand{\gtilde}{\char"7E}
\newcommand{\ghat}{\char"5E}
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