% 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 24.1.18.3, p. III-305.
% Original source in file "macros4.TEX", starting line 1230.
\wlog{L: "droppre.tip" ["macros4.TEX," l. 1230, p. III-305]}%
% This file DOES belong to format "texip."
\InputD{isprefix.tip}
\InputD{showx.tip}
\catcode`\@ = 11
\def\DropPrefix #1#2#3{%
    \if\PrefixConditional{#1}{#2}%
        \edef\@PrefixConditionalTemp{% 
            \def\noexpand\@PrefixConditionalTempTwo #2####1% 
                                        \noexpand\@Del{%
                \def\noexpand #3{####1}}%
        }%
        \@PrefixConditionalTemp
        \ShowX{\@PrefixConditionalTemp}%
        \expandafter\@PrefixConditionalTempTwo #1\@Del
    \else
        \wlog{\string\DropPrefix: "#2" is NOT a prefix of "#1"}%
        \edef#3{#1}%
    \fi
}
\catcode`\@ = 12