%  Boolean --- Boolean expressions
%
%  Copyright (C) 2006 Didier Rémy
%
%  Author         : Didier Remy 
%  Version        : 0.1
%  Bug Reports    : to author
%  Web Site       : http://pauillac.inria.fr/~remy/latex/
% 
%  Boolean 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, or (at your option)
%  any later version.
%  
%  Boolean 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 
%  (http://pauillac.inria.fr/~remy/license/GPL).
%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%  File boolean.sty (LaTeX macros)
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

\NeedsTeXFormat{LaTeX2e}
\ProvidesPackage{boolean}
    [2006/10/05 version 0.1  Boolean expressions]

%% This package  provides LaTeX with boolean expressions 

%% Identification
%% Preliminary declarations
%% Options


\newcommand {\TRUE}[2]{#1}
\newcommand {\FALSE}[2]{#2}

%% Public commands are also given inner hidden names

\let \bln@true \TRUE
\let \bln@false \FALSE

\newcommand {\AND}[2]{#1{#2}{\bln@false}}
\newcommand {\OR}[2]{#1{\bln@true}{#2}}
\newcommand {\NOT}[1]{#1{\bln@false}{\bln@true}}
\newcommand {\IF}[3]{#1{#2}{#3}}

\let \bln@and \AND
\let \bln@or  \OR
\let \bln@not \NOT
\let \bln@if  \IF


%% To convert if.. macros into Booleans: 

\newcommand {\texbool}[1]
    {#1\let \bln@do \bln@true \else \let \bln@do \bln@false\fi \bln@do}
%% Does not work
\let \bln@tex \texbool

\newcommand {\ifxbool}[2]
    {\ifx #1#2\let \bln@do \bln@true \else \let \bln@do \bln@false \fi \bln@do}
\let \bln@ifx \ifxbool

\newcommand {\ifybool}[2]
    {\def \bln@testa{#1}\ifxbool{\bln@testa}{#2}}
\let \bln@ify \ifybool

\newcommand {\ifequalbool}[2]
    {\def \bln@testa{#1}\def \bln@testb{#2}\ifxbool{\bln@testa}{\bln@testb}}
\let \bln@ifequal \ifequalbool

\def \bln@empty {}
\newcommand {\ifemptybool}[1]
    {\ifybool{#1}{\bln@empty}}
\let \bln@ifempty \ifemptybool

%% To force evaluation, e.g. if a blnlean expression is to be used several
%% times. This takes a Boolean expression and returns a Boolean value, i.e. 
%% \True or \False.

\newcommand* {\letboolval}[2]
        {#2{\let #1\bln@true}{\let #1\bln@false}}
\newcommand* {\newboolval}[2]
        {\@ifdefinable #1{\letboolval{#1}{#2}}}

%% We provide list versions of And and Or

\def \bln@scan #1,#2\bln@to#3#4{%
    \bln@ifempty{#2}{#3{#4}{#1}}
          {\bln@scan #2\bln@to {#3}{#3{#4}{#1}}}%
}
\def \bln@eval #1#2#3{%
    \bln@ifempty{#1}{#3}%
          {\bln@scan #1,\bln@to {#2}{#3}}%
}

\newcommand*{\ANDL}[1]{\bln@eval {#1}{\bln@and}{\bln@true}}
\newcommand*{\ORL} [1]{\bln@eval {#1}{\bln@or}{\bln@false}}

%% In some contexts, shorter names may be more convenient

\newcommand*{\ShorterBooleanNames}{%
  \let \true  \bln@true
  \let \false \bln@true
  \let \or    \bln@or
  \let \and   \bln@and
  \let \not   \bln@not
  \let \orl   \bln@orl
  \let \andl  \bln@andl
}

%% Comparisson between strings 

\newcommand {\stringmatch}[3]{%
   \def \@match ##1#2##2\str@sep ##3\str@sep ##4\str@end
        {#1{##1}{##2}{\ifequalbool{#2}{##3}}}%
   \@match #3\str@sep #2\str@sep \str@sep \str@end
}
\let \str@match \stringmatch

%% The following commands takes in order Prefix Infix Suffix Left

\def \str@infix  #1#2#3{#3}
\def \str@prefix #1#2#3{\AND{#3}{\ifemptybool{#1}}}
\def \str@suffix #1#2#3{\AND{#3}{\ifemptybool{#2}}}

\newcommand {\ifstringinfix} {\str@match {\str@infix}}
\newcommand {\ifstringsuffix}{\str@match {\str@suffix}}
\newcommand {\ifstringprefix}{\str@match {\str@prefix}}