%
% sortlist.sty
%
% Implements a sorted list, with handler functions.
%
%
\ProvidesFile{sortlist}[2005/02/12 Sorted list]
\RequirePackage{strings}
%
% Create a new list. Requires three arguments: a name for the list, a sorting
% function, and a function definition that determines what elements to sort:
%
%   \NewSortedList{list}{\SortAlpha}{#1}
%   which would create a list named ``list'' which is sorted alphabetically and
%   uses the elements of the list as sorting keys.
%
% Lists are implemented as token lists.
%
% The key finding function should be totally expandable. The sorting function
% need not be.
\def\NewSortedList#1#2{%
    \expandafter\newtoks\csname sli@@#1\endcsname
    \@namedef{sli@fn@#1}{#2}%
    \expandafter\def\csname sli@k@#1\endcsname##1##2%
}
\def\IfEmptyList#1{%
    \@expand\@ifempty{\expandafter\the\csname sli@@#1\endcsname}{ii}%
}
\def\sli@namelet#1#2{\expandafter\sli@@namelet\csname #2\endcsname#1}%
\def\sli@@namelet#1#2{\let#2#1}%
\def\ReverseSort#1#2#3{%
    #1{#2}{#3}\ifCompReverse\CompReversefalse\else\CompReversetrue\fi
}
\def\AddToList#1#2{%
    \sli@namelet\sli@this{sli@@#1}%
    \sli@namelet\sli@sfun{sli@fn@#1}%
    \sli@namelet\sli@kfun{sli@k@#1}%
    \def\sli@elt{#2}\sli@kfun{#2}\sli@addkey
    \let\sli@do\relax
    \edef\sli@act{%
	\noexpand\sli@this{}% Clear the list
	\noexpand\sli@add{}%
	\the\sli@this
	\noexpand\sli@stop\relax
    }%
    \sli@act
}
\def\sli@stop{\sli@stop}
\def\sli@add#1#2#3{%
    \ifx\sli@stop#2%
	% If at the end of the list, pop the element on the end of the list
	\edef\sli@act##1{%
	    \sli@this{##1\sli@do{\expandafter\noexpand\sli@elt}}%
	}%
	\sli@act{#1}%
    \else
	% \sli@key ends up looking like {new-key}{key}
	\sli@kfun{#3}\sli@key
	\sli@exptwice\sli@key\sli@key\sli@addkey
	% So this ends up running \sli@sfun{new-key}{key}
	\expandafter\sli@sfun\sli@key
	\@test\ifCompReverse\fi
	{%
	    \edef\sli@act##1##2{\sli@this{%
		##1\sli@do{\expandafter\noexpand\sli@elt}\sli@do{##2}%
	    }}\sli@act{#1}{#3}%
	    \expandafter\sli@addend
	}{%
	    \@skipafi{\sli@add{#1\sli@do{#3}}}
	}%
    \fi
}
\def\sli@exptwice#1#2#3{\@expand{\@expand{\sli@@exptwice{#1}}{#2}{i}}{#3}{i}}
\def\sli@@exptwice#1#2#3{\def#1{{#2}{#3}}}
\def\sli@addend#1\sli@stop\relax{%
    \edef\sli@act##1{\sli@this{\the\sli@this##1}}\sli@act{#1}%
}
\newif\ifCompReverse
\def\SortNum#1#2{%
    \@tempcnta#1\relax \@tempcntb#2\relax
    \ifnum\@tempcnta>\@tempcntb \CompReversetrue \else \CompReversefalse \fi
}
\def\NoSort#1#2{\CompReversefalse}
\def\SortLen#1#2{\sli@sortlen#1\sli@stop\@nil#2\sli@stop\@nil}
\def\sli@sortlen#1#2\@nil#3#4\@nil{%
    \@test{\ifx#1\sli@stop}\fi{%
	\CompReversefalse
    }{%
	\@test{\ifx#3\sli@stop}\fi{%
	    \CompReversetrue
	}{%
	    \sli@sortlen#2\@nil#4\@nil
	}%
    }%
}%
\def\@ifbothonechar#1#2{\@ifonechar{#1}{\@ifonechar{#2}}{\@secondoftwo}}
\def\SortAlpha#1#2{\sli@alpha#1\sli@stop\@nil#2\sli@stop\@nil}
\def\sli@alpha#1#2\@nil#3#4\@nil{%
    \@ifbothonechar{#1}{#3}{%
	\sli@alpha@bothonechar#1{#2}#3{#4}%
    }{%
	% Group found inside argument. Expand it.
	\sli@alpha#1#2\@nil#3#4\@nil
    }%
}
\def\sli@alpha@bothonechar#1#2#3#4{%
    \ifcat\noexpand#3\relax
	% #3 is a control sequence, but not \sli@stop
	\expandafter\sli@alpha@chkthree
    \else
	\expandafter\sli@alpha@onecs
    \fi
    % Args to whichever command is chosen
    #1{#2}#3{#4}%
}
\def\sli@alpha@onecs#1{%
    \ifcat\noexpand#1\relax
	\expandafter\sli@alpha@chkone
    \else
	\expandafter\sli@alpha@chars
    \fi
    #1% Put it back onto token list
}
\def\sli@alpha@chkone#1#2#3#4{%
    \ifx#1\sli@stop
	\CompReversefalse
    \else
	\@skipafi{\sli@alpha#2\@nil#3#4\@nil}%
    \fi
}
\def\sli@alpha@chkthree#1#2#3#4{%
    \ifx#3\sli@stop
	\CompReversetrue
    \else
	\@skipafi{\sli@alpha#1#2\@nil#4\@nil}%
    \fi
}
\def\sli@alpha@chars#1#2#3#4{%
    % Both #1 and #3 are characters.
    \@test\ifnum`#1>`#3 \fi{%
	% First char is greater than second
	\CompReversetrue
    }{%
	\@test\ifnum`#1=`#3 \fi{%
	    % Chars are equal.
	    \sli@alpha#2\@nil#4\@nil
	}{%
	    % Second char is greater than the first.
	    \CompReversefalse
	}%
    }%
}
\def\ShowList#1{%
    \def\sli@act{\expandafter\the\csname sli@@#1\endcsname}%
    \afterassignment\sli@act\def\sli@do##1%
}
\endinput