% This macro source file is from the four volume series
% "TeX in Practice" by Stephan von Bechtolsheim, published
% 1993 by Springer-Verlag, New York.
% Copyright 1993 Stephan von Bechtolsheim.
% No warranty or liability is assumed.
% This macro may be copied freely if no fees other than
% media cost or shipping charges are charged and as long
% as this copyright and the following source code itself
% is not changed. Please see the series for further information.
%
% Version: 1.0
% Date: May 1, 1993
%
%
% This source code is documented in 27.1.8, p. III-412.
% Original source in file "macros7.TEX", starting line 768.
\wlog{L: "doloop.tip" ["macros7.TEX," l. 768, p. III-412]}%
% This file DOES belong to format "texip."
\catcode`\@ = 11
\newcount\@DoLoopNesting
\@DoLoopNesting = 0
\newcount\@DoLoopLimit
\newcount\@DoLoopLimitTwo
\newcount\@DoLoopLimitThree
\def\DoLoop #1#2#3#4#5{%
\global\advance\@DoLoopNesting by 1
\ifnum\@DoLoopNesting > 3
\errmessage{\string\DoLoop: nesting beyond three levels
is not supported.}%
\fi
\ifnum #3 = 0
\errmessage{\string\DoLoop: step value (parameter 3) is 0!}%
\else
\ifcase\@DoLoopNesting
\or
\@DoLoop{#1}{#2}{#3}{#4}{#5}%
{\@DoLoopLimit}{\DoLoopBody}%
\or
\@DoLoop{#1}{#2}{#3}{#4}{#5}%
{\@DoLoopLimitTwo}{\DoLoopBodyTwo}%
\or
\@DoLoop{#1}{#2}{#3}{#4}{#5}%
{\@DoLoopLimitThree}{\DoLoopBodyThree}%
\fi
\fi
\global\advance\@DoLoopNesting by -1
}
\def\@DoLoop #1#2#3#4#5#6#7{%
\ifnum #3 > 0
#6 = #4%
\advance#6 by 1
#1 = #2%
\@DoLoopBodyPositive{#1}{#3}{#5}%
{#6}{#7}%
\else
#6 = #4%
\advance#6 by -1
#1 = #2%
\@DoLoopBodyNegative{#1}{#3}{#5}%
{#6}{#7}%
\fi
\@DoLoopIterate{#7}%
}
\def\@DoLoopBodyPositive #1#2#3#4#5{%
\def #5{%
\ifnum #1 < #4\relax
#3%
\advance #1 by #2%
}%
}
\def\@DoLoopBodyNegative #1#2#3#4#5{%
\def #5{%
\ifnum #1 > #4\relax
#3%
\advance #1 by #2%
}%
}
\def\@DoLoopIterate #1{%
#1\relax
\def\@DoLoopNext{\@DoLoopIterate{#1}}%
\else
\def\@DoLoopNext{\relax}%
\fi
\@DoLoopNext
}
\catcode`\@ = 12
