44 lines
1.9 KiB
Text
44 lines
1.9 KiB
Text
__HEADER__(Find a package that provides some command)
|
|
% This is just a quick packaging of the post by
|
|
% 'Martin Nyolt' (https://tex.stackexchange.com/users/78783/martin-nyolt)
|
|
% found at
|
|
% https://tex.stackexchange.com/users/78783/martin-nyolt
|
|
% Note that SO answers are by default CC BY-SA 3.0 licensed, see
|
|
% https://creativecommons.org/licenses/by-sa/3.0/
|
|
|
|
\def\find@load#1[#2]#3[#4]{%
|
|
% load the package
|
|
\find@fileswith@pti@ns{#1}[#2]{#3}[#4]%
|
|
% check if commands exists now
|
|
\ifcsname\find@command\endcsname
|
|
\typeout{Package #3 introduces command \find@command.}%
|
|
% command has been found, revert to original version without checks
|
|
\let\@fileswith@pti@ns\find@fileswith@pti@ns
|
|
\else
|
|
% somehow, \@fileswith@pti@ns is restored after loading a package
|
|
% thus, patch it again
|
|
\let\@fileswith@pti@ns\find@load
|
|
\fi
|
|
}%
|
|
|
|
\newcommand*{\findpackagebycommand}[1]{%
|
|
% using this multiple times - esp. when the package has not been found yet -
|
|
% will break things. Thus, check first that \find@command has never been defined before
|
|
\ifx\find@command\undefined
|
|
\def\find@command{#1}%
|
|
% first, check if this command is already defined
|
|
\ifcsname\find@command\endcsname
|
|
% in this case, just issue a warning and do nothing
|
|
\@latex@warning@no@line{Command \find@command \space is already defined}%
|
|
\else
|
|
% overwrite the internal \@fileswith@pti@ns command, which does the actual loading
|
|
% \@fileswith@pti@ns is used internally by \usepackage and \RequirePackage
|
|
\let\find@fileswith@pti@ns\@fileswith@pti@ns
|
|
\let\@fileswith@pti@ns\find@load
|
|
\fi
|
|
\else
|
|
% used multiple times - prevent and give a warning
|
|
\@latex@warning@no@line{You can use \protect\findpackagebycommand \space only once}%
|
|
\errmessage{Invalid use of command findpackagebycommand.}%
|
|
\fi
|
|
}
|