% 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 23.4.4.2, p. III-258.
% Original source in file "macros3.TEX", starting line 1127.
\wlog{L: "dblarg.tip" ["macros3.TEX," l. 1127, p. III-258]}%
% This file DOES belong to format "texip."
\InputD{futlet.tip}
\catcode`\@ = 11
\def\DblArg #1{% 
    \def\@DblArgTemp{#1}%
    \DoFutureLet{\ifx}{[}{\@DblArgTemp}{\@DblArgB}%
}
\def\@DblArgB #1{\@DblArgTemp[#1]{#1}}
\catcode`\@ = 12