pseudocode.sty

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%                                                                     %
% pseudocode.sty, by Dario Sneidermanis.                              %
%                                                                     %
% Based on package `clrscode3e', written by Thomas H. Cormen:         %
%                                                                     %
% Package for producing pseudocode in the style of Cormen, Leiserson, %
% Rivest, and Stein, Introduction to Algorithms, Third edition.       %
%                                                                     %
% http://www.cs.dartmouth.edu/~thc/clrscode/                          %
%                                                                     %
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%


\ProvidesPackage{pseudocode}


\RequirePackage{graphics}
\RequirePackage{xparse}


%%%%%%%%%%%%%%%%%%%%%%%
% Formatting commands %
%%%%%%%%%%%%%%%%%%%%%%%


% Typesets constants.
% Usage examples:
%   \const{true}
%   \const{nil}
\newcommand{\const}[1]{\textnormal{\scshape#1}}

% Typesets variables.
% Usage examples:
%   \var{key}
%   \var{left-sum}
%   \var{i}
\newcommand{\var}[1]{\ensuremath{\hspace*{-0.5pt}\mathit{\text@hyphens#1}}}

% Typesets functions.
% Usage examples:
%   \func{Insertion-Sort}{}
%   \func{Dijkstra}{G, s}
%   \func{Dijkstra}{G = graph, s = vertex}
\NewDocumentCommand{\func}{m g} {\@@function{\textnormal{\scshape#1}}{#2}}

% Typesets fixed functions.
% Usage examples:
%   \fixfunc{sin}{x}
%   \fixfunc{out-degree}{G, v}
\NewDocumentCommand{\fixfunc}{m g} {%
    \@@function{\ensuremath{{\mathop{\text@hyphens\operator@font#1}\nolimits}}}{#2}%
}

% Typesets object attributes.
% Usage examples:
%   \member{user}{name}
\newcommand{\member}[2]{\var{#1}\ensuremath{.\@@tsp\@@tsp}\var{#2}}

% Typesets array elements.
% Usage examples:
%   \at{names}{pos}
\newcommand{\at}[2]{\ensuremath{\var{#1}\@@tsp[\@@surround{\var{#2}}]}}

% Typesets keywords.
% Usage examples:
%   \keyword{for}
%   \keyword{if}
\newcommand{\kw}[1]{\textbf{#1}}

% Symbol for typesetting subarray ranges.
% Usage examples:
%   $[1 \twodots n]$
\newcommand{\twodots}{\mathinner{\ldotp\ldotp}}


%%%%%%%%%%%%%%%%%%%%%%%%%%%
% Pseudocode2 environment %
%%%%%%%%%%%%%%%%%%%%%%%%%%%


\newif\if@@activepseudocode\@@activepseudocodefalse

\newcounter{@@indentlevel}

\NewDocumentEnvironment{pseudocode2}{o}
{%
    \if@@activepseudocode\PackageError{pseudocode}{Nested pseudocode environments not supported!}\fi%
    \global\@@activepseudocodetrue%
    \setcounter{@@indentlevel}{0}%
    \newenvironment{block}{\addtocounter{@@indentlevel}{1}}{\addtocounter{@@indentlevel}{-1}}%
    \addtolength{\topsep}{0.5ex}%
    \def\@@indent{\textbf{else} }%
    \begin{trivlist}%
        \item\parindent=0pt%
        \@nobreaktrue\IfValueT{#1}{#1\rule[-2ex]{0pt}{0pt}\\}%
        \begin{minipage}[t]{1000pt}% TODO: fix this hardcoded size
            \begin{tabbing}%
                99\=\@@indent\=\@@indent\=\@@indent\=\@@indent\=\@@indent\=\@@indent\=\@@indent\=\@@indent\=\@@indent\=\+\kill%
} {%
            \end{tabbing}%
        \end{minipage}%
    \end{trivlist}%
    \addtolength{\topsep}{-0.5ex}%
    \global\@@activepseudocodefalse%
}


%%%%%%%%%%%%%%%%%%%%%%%%%%
% Pseudocode environment %
%%%%%%%%%%%%%%%%%%%%%%%%%%


% When we make a pseudocode, we save the code part into a box before printing it.
% We do not actually print the code until we know how many line numbers there
% are.
\newsavebox{\savecode}

% The \ifprocname command tells us whether this procedure has been given a name.
% yet.
\newif\ifprocname

% The \iffirstcodeline command tells us whether we are about to produce the
% first line other than the procedure declaration.
\newif\iffirstcodeline

% \digitwidth gives the width of a single digit.  All digits are the same width.
% We'll need this amount to do the right thing for line numbers.
\newlength{\digitwidth}
\settowidth{\digitwidth}{0}

% Assume that the width of the pseudocode is the width of the text, minus the width
% of 2 digits.  We'll correct for that later.
\newlength{\pseudocodewidth}
\setlength{\pseudocodewidth}{\linewidth} % Thanks, David Etherington!
\addtolength{\pseudocodewidth}{-2\digitwidth}

% The codelinenumber counter counts the current line number.
\newcounter{codelinenumber}

% The indent counter keeps track of the current indentation level.
\newcounter{indent}

% The "pseudocode" environment produces an unbreakable section of code.
\newenvironment{pseudocode}{%
    % this proc hasn't been given a name yet
    \global\procnamefalse%
    % producing the first line
    \setcounter{codelinenumber}{0}%
    \setcounter{indent}{0}%
    \firstcodelinetrue%
    % distance between numbers and code
    \setlength{\tabbingsep}{1em}%
    % Initialize \@lilabel to allow a pageref \label cmd at the beginning of the
    % pseudocode
    \global\let\@lilabel\@currentlabel
    \def\@currentlabel{\@lilabel}%
    % save the code into a box
    \begin{lrbox}{\savecode}%
    % it'll be a minipage
    \begin{minipage}[t]{\pseudocodewidth}%
    % set up the tab stops
    \def\codeindent{\textbf{else} }%
    \begin{tabbing}%
    99\=\codeindent\=\codeindent\=\codeindent\=\codeindent\=\codeindent\=\codeindent\=\codeindent\=\codeindent\=\codeindent\=\+\kill%
}{%
    % Here's what's run at the end of a pseudocode environment.  Start by making
    % sure that we have ended at indent level 0.  Otherwise, print a warning.
    \ifnum\value{indent}=0\else\typeout{Warning: Indentation ends at level \theindent\space in pseudocode on page \thepage.}\fi%
    % close all open environments
    \end{tabbing}%
    \end{minipage}%
    \end{lrbox}%
    % for the following trivlist
    \addtolength{\topsep}{0.5ex}%
    \begin{trivlist}\item\parindent=0pt%
        % If there was a procedure name given, print it now but with a little
        % space below, and disallow a page break after the procedure name.
        \@nobreaktrue%
        \ifprocname\saveprocname\rule[-2ex]{0pt}{0pt}\\ \fi%
        % Put in the right amount of space, depending on whether we reached
        % double digits in the line numbers.
        \ifnum\value{codelinenumber}>9\hspace*{2\digitwidth}\else\hspace*{1\digitwidth}\fi%
        % Now print the code
        \usebox{\savecode}%
    \end{trivlist}%
    \addtolength{\topsep}{-0.5ex}%
}


%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% Pseudocode environment commands %
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%


% Function name.
\NewDocumentCommand{\function}{ m g } {%
    \global\def\saveprocname{\func{#1}{#2}}%
    \global\procnametrue%
}


%%%%%%%%%%%%%%%%%%%%%%%%%%
% Pseudocode indentation %
%%%%%%%%%%%%%%%%%%%%%%%%%%


% counter for recursive indenting code.
\newcounter{thisindent}

% \putindents is a recursive macro that indents a number of times given by the
% counter thisindent.
\newcommand{\putindents}{%
    \ifnum\value{thisindent}>0\>\addtocounter{thisindent}{-1}\putindents\fi%
}

\newcommand{\Indent}{\setcounter{thisindent}{\value{indent}}\putindents}



% Indent the next line one level more.
\newcommand{\Indentmore}{\addtocounter{indent}{1}}


% should this line have a number.
\newif\ifnumberedline\numberedlinetrue

% \liprint actually prints the line number and sets up the indentation.
\newcommand{\liprint}{%
    \protected@xdef\@lilabel{\thecodelinenumber}%
    \ifnumberedline\thecodelinenumber\fi\'\Indent%
}

% The \li command starts a new numbered line. The optional defines sets with a
% little extra the space above.
\newcommand{\li}[1][2pt]{%
    \global\numberedlinetrue%
    \iffirstcodeline\global\firstcodelinefalse\else\\[#1] \fi
    \stepcounter{codelinenumber}%
    \liprint%
}

\newcommand{\liempty}{\li[0pt]\li[0pt]}


\providecommand{\numref}[1]{%
  \@ifundefined{r@#1}{000}{%
    \expandafter\expandafter\expandafter\@firstoftwo
    \csname r@#1\endcsname
  }%
}

% \setlinenumber sets the line number to its argument.
\newcommand{\setlinenumber}[1]{%
    \setcounter{codelinenumber}{\numref{#1}}%
    \addtocounter{codelinenumber}{-1}%
}

% \setlinenumberplus sets the line number to its first argument plus its second
% argument.
\newcommand{\setlinenumberplus}[2]{%
    \setcounter{codelinenumber}{\numref{#1}}%
    \addtocounter{codelinenumber}{-1}\addtocounter{codelinenumber}{#2}%
}

% The \zi command starts a new unnumbered line.
\newcommand{\zi}{%
    \global\numberedlinefalse%
    \iffirstcodeline\global\firstcodelinefalse\else\\ \fi
    \liprint%
}

% Temporarily make all lines indented so that they start at the end of a given
% text.
\newcommand{\Startalign}[1]{\\ \pushtabs\FakeIndent#1\=\kill}
\newcommand{\Stopalign}{\poptabs}
\newcommand{\FakeIndent}{\setcounter{thisindent}{\value{indent}}\putfakeindents}
\newcommand{\putfakeindents}{\ifnum\value{thisindent}>0\textbf{else }\addtocounter{thisindent}{-1}\putfakeindents\fi}


%%%%%%%%%%%%
% Keywords %
%%%%%%%%%%%%


\newcommand{\For}{\textbf{for} }
\newcommand{\To}{\ifmmode\ \textrm{\textbf{to}}\ \else\textbf{to}\ \fi}
\newcommand{\By}{\ifmmode\ \textrm{\textbf{by}}\ \else\textbf{by}\ \fi}
\newcommand{\Downto}{\ifmmode\ \textrm{\textbf{downto}}\ \else\textbf{downto}\ \fi}
\newcommand{\While}{\textbf{while} }
\newcommand{\Repeat}{\textbf{repeat}\>\addtocounter{indent}{1}}
\newcommand{\Until}{\kill\addtocounter{indent}{-1}\liprint\textbf{until} }
\newcommand{\If}{\textbf{if} }
\newcommand{\Then}{\>\addtocounter{indent}{1}}
\newcommand{\Else}{\kill\addtocounter{indent}{-1}\liprint\textbf{else}\>\addtocounter{indent}{1}}
\newcommand{\End}{\addtocounter{indent}{-1}}
\newcommand{\ElseIf}{\kill\addtocounter{indent}{-1}\liprint\textbf{elseif} }
\newcommand{\ElseNoIf}{\kill\addtocounter{indent}{-1}\liprint\textbf{else} \addtocounter{indent}{1}}
\newcommand{\Do}{\>\addtocounter{indent}{1}}
\newcommand{\Return}{\textbf{return} }
\newcommand{\CommentSymbol}{\texttt{\textbf{/\hspace*{-0.3em}/}}}
\newcommand{\Comment}{\CommentSymbol\ }
\newcommand{\RComment}{\`\CommentSymbol\ }
\newcommand{\Goto}{\textbf{goto} }
\newcommand{\Error}{\textbf{error} } % optionally followed by string argument.
\newcommand{\EndTest}{\textbf{:}}
\newcommand{\Spawn}{\ifmmode\textbf{spawn}\ \else\textbf{spawn} \fi}
\newcommand{\Sync}{\textbf{sync}}
\newcommand{\Parfor}{\textbf{parallel for} }


%%%%%%%%%%%%%%%%
% Misc helpers %
%%%%%%%%%%%%%%%%


% Tiny space.
\newcommand{\@@tsp}{\hspace*{0.5pt}}

% Forces hyphens.
\newcommand{\text@hyphens}{\mathcode`\-=`\-\relax}


%%%%%%%%%%%%%%%%%%%%%
% @@function helper %
%%%%%%%%%%%%%%%%%%%%%


% Tells if we are parsing the first function argument.
\newif\if@@firstarg

% Typesets function calls/declarations.
\NewDocumentCommand{\@@function}{m >{\SplitList{,}} g} {%
    #1%
    \IfValueT{#2} {%
        \textrm{\@@tsp(%
            \@@surround{%
                \global\@@firstargtrue%
                \ProcessList{#2}{\@@parsearg}%
                \global\@@firstargfalse%
            }%
        )}%
    }%
}

% Splits a function argument.
\NewDocumentCommand{\@@parsearg}{>{\SplitArgument{1}{:}} m} {\@@printarg#1}

% Parses a function argument.
\NewDocumentCommand{\@@printarg}{m m} {%
    \if@@firstarg\global\@@firstargfalse\else{\textit{,\ }}\fi%
    \var{#1}%
    \IfValueT{#2} {\textrm{\@@tsp :\ #2\@@tsp}}%
}


%%%%%%%%%%%%%%%%%%%%%
% @@surround helper %
%%%%%%%%%%%%%%%%%%%%%


% Holds the width of the text being surrounded.
\newlength{\@@paramlen}

% Holds the maximum accepted length without spaces.
\newlength{\@@maxlen}\settowidth{\@@maxlen}{\var{W}}

% Surrounds text with spaces depending on its length.
\newcommand{\@@surround}[1]{%
    \settowidth{\@@paramlen}{\var{#1}}%
    \ifdim\@@paramlen>\@@maxlen\@@tsp\@@tsp\@@tsp\fi%
    #1%
    \ifdim\@@paramlen>\@@maxlen\@@tsp\@@tsp\fi%
}

\endinput