microalg.sty

\NeedsTeXFormat{LaTeX2e}[1994/06/01]
\ProvidesPackage{microalg}[2017/01/31]

% Based on this question :
% http://tex.stackexchange.com/questions/235740/how-can-i-color-parentheses-depending-on-the-nesting-level-like-emacs-rainbow

\RequirePackage{listings}
\RequirePackage{xcolor}

\definecolor{color0}{RGB}{255, 170, 187}
\definecolor{color1}{RGB}{255, 221, 187}
\definecolor{color2}{RGB}{255, 255, 187}
\definecolor{color3}{RGB}{221, 255, 187}
\definecolor{color4}{RGB}{204, 238, 255}
\definecolor{color5}{RGB}{221, 204, 255}
\definecolor{color6}{RGB}{187, 187, 238}

\lstdefinelanguage{microalg}{
  morekeywords = {deffunction, deftemplate, defrule, deffacts, run,
    clear, reset, facts, agenda, nil, initial-fact, assert, retract,
    watch, ppdefrule, unwatch, crlf},
  sensitive        = true,
  morecomment      = [l]{;},
  morestring       = [b]",
  basicstyle       = \ttfamily\small,
  numbers          = left,
  numberstyle      = \tiny,
  showstringspaces = false,
}

% egreg's modulo macro (see http://tex.stackexchange.com/a/34449/21891)
\def\truncdiv#1#2{((#1-(#2-1)/2)/#2)}
\def\moduloop#1#2{(#1-\truncdiv{#1}{#2}*#2)}
\def\modulo#1#2{\number\numexpr\moduloop{#1}{#2}\relax}


\makeatletter

% a TeX counter to keep track of the nesting level
\newcount\netParensCount@microalg

% Modify how ( and ) get typeset depending on the value of the counter
% (Based on Ulrike Fischer's approach to modifying characters in listings;
% see http://tex.stackexchange.com/a/231927/21891)
\lst@CCPutMacro
\lst@ProcessOther{`(}{{%
  \ifnum\lst@mode=\lst@Pmode\relax%
    \rainbow@microalg{(}%
    \global\advance\netParensCount@microalg by \@ne%
  \else
    (%
  \fi
}}%
\lst@ProcessOther{`)}{{%
  \ifnum\lst@mode=\lst@Pmode\relax%
    \global\advance\netParensCount@microalg by \m@ne%
    \rainbow@microalg{)}%
  \else
    )%
  \fi
}}%
\@empty\z@\@empty

% Color its argument based on the value of the \netParensCount@microalg counter
% (modulo 7)
\newcommand\rainbow@microalg[1]{%
  \ifcase\modulo\netParensCount@microalg 7\relax%
    \colorbox{color0}{\makebox[0em]{#1}}%
  \or
    \colorbox{color1}{\makebox[0em]{#1}}%
  \or
    \colorbox{color2}{\makebox[0em]{#1}}%
  \or
    \colorbox{color3}{\makebox[0em]{#1}}%
  \or
    \colorbox{color4}{\makebox[0em]{#1}}%
  \or
    \colorbox{color5}{\makebox[0em]{#1}}%
  \else
    \colorbox{color6}{\makebox[0em]{#1}}%
  \fi
}

% Alternatively, you could simplify the definition of \rainbow@microalg to...
% \newcommand\rainbow@microalg[1]{%
%   \textcolor{color\modulo\netParensCount@microalg 7}{#1}%
% }
% ... but this assumes that the colours have names of the form color<i>,
% where <i> is a positive integer

% reset the counter at the beginning of each listing
% (just in case there were unmatched parentheses in a previous listing)
\lst@AddToHook{PreInit}{%
  \global\netParensCount@microalg 0\relax%
}

\makeatother


\lstnewenvironment{microalg}
  {\lstset{language=microalg}}
  {}

\endinput