% Usage: 
%
%   \DeclareSwitch{XXX}
%
% If \ifXXX is undefined, this is equivalent to:
%
%   \newif\ifXXX
%   \XXXfalse
%
% Otherwise it does nothing.

% This file may be loaded many times.  On the first time, we want to
% use \newcommand.  On subsequent occasions, we want to use
% \CheckCommand.

\@ifundefined{DeclareSwitch}{\newcommand}{\CheckCommand}
  {\DeclareSwitch}[1]
  {\@ifundefined{if#1}%
    {% First, allocate the new boolean switch.
     \expandafter\newif\csname if#1\endcsname
     % Then initialize it to false.
     \csname #1false\endcsname}%
    {% We should check here that it is a proper boolean, but that is difficult.
    }%
   \message{(if#1=if\csname if#1\endcsname true\else false\fi)}}