In the next MWE, the test provided on a macro parameter gives the expected answer (it finds if the parameter begins with a (
), but the same test fails on or ignores the pgfkey it has to test.
This is a minimal example, it is to finish my answer to this question : How to define at tikz style option to draw a dimension line between to specific points
\documentclass{article}
\usepackage{xparse,tikz}
\usetikzlibrary{calc}
\usepackage{ifluatex}
\makeatletter
\ifluatex
\RequirePackage{pdftexcmds}
\let\pdfstrcmp\pdf@strcmp
\let\pdffilemoddate\pdf@filemoddate
\fi
\tikzset{%
Cote/.style={to path={\pgfextra{
\pgfinterruptpath
\draw[>=latex,|<->|] let
\p1=($(\tikztostart)!2mm!90:(\tikztotarget)$),
\p2=($(\tikztotarget)!2mm!-90:(\tikztostart)$)
in(\p1) -- (\p2) node[pos=.5,sloped,above]{%
\expandafter\Cote\expandafter{\@aspect} --
\expandafter\CoteBis{$\pi$}\expandafter<\@aspect>};
\endpgfinterruptpath
}(\tikztostart) -- (\tikztotarget) \tikztonodes}}
}
\pgfkeys{tikz/Cote/.cd,
aspect/.store in=\@aspect,
aspect=o,
}
\makeatletter
\NewDocumentCommand{\Cote}{m}{%
\ifnum\pdfstrcmp{\unexpanded\expandafter{\@car#1\@nil}}{(}=\z@
true
\else
false
\fi
}
\NewDocumentCommand{\CoteBis}{md<>
}{%
#1
\ifnum\pdfstrcmp{\unexpanded\expandafter{\@car#2\@nil}}{(}=\z@
true
\else
false
\fi
}
\makeatother
\begin{document}
\verb+\Cote+ : \Cote{(F)} -- \Cote{F} : The test gives the expected answers
\verb+\Codetis+ : \CoteBis{$\pi$}<(F)> -- \CoteBis{$\pi$}<F> : The test gives the expected answers
\bigskip
In the \verb+\Cote+ macro, the test gives the expected answers
In the \verb+\CoteBis+ macro, the test gives unexpected answers
\bigskip
\begin{tikzpicture}
\path[Cote/aspect=F] (0,0) to[Cote] (5,0) ;
\path[Cote/aspect=(F)] (0,1) to[Cote] (5,1) ;
\end{tikzpicture}
\end{document}