% 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 23.4.8.1, p. III-266.
% Original source in file "macros3.TEX", starting line 1514.
\wlog{L: "defauarg.tip" ["macros3.TEX," l. 1514, p. III-266]}%
% This file DOES belong to format "texip."
\InputD{gobblemo.tip}
\catcode`\@ = 11
\def\DefaultArg #1#2#3{%
    \def\@DefaultArgMacro{#1}%
    \edef\@EmptyOtherArg{#2}%
    \edef\@DefaultArgDefault{#3}%
    \@DefaultArg #2\@DefaultArgEnd
}
\def\@DefaultArg{%
    \futurelet\@DefaultArgSymbol\@DefaultArgOne
}
\def\@DefaultArgOne{%
    \ifx\@DefaultArgSymbol\@DefaultArgEnd
        \expandafter\edef\@DefaultArgMacro{\@DefaultArgDefault}% 
    \else
        \expandafter\edef\@DefaultArgMacro{\@EmptyOtherArg}% 
    \fi
    \GobbleDoMore{\@DefaultArgEnd}{\relax}%
}
\catcode`\@ = 12