Check if multiple column types are defined fails

Question

Using the commands of the discussion How to check if a column type is defined? and How to implement a command that checks for loaded packages?

I have build an enviroment to check if more than one column is defined

\documentclass{scrbook}
\usepackage{etoolbox}
\usepackage{ragged2e}
\usepackage{array}
\makeatletter
\newcommand\CheckIfColumntypeDefined[1]{%
  \providebool{tpl@coltype@#1}
  \ifcsdef{NC@find@\string#1}%
    {\setbool{tpl@coltype@#1}{true}}%
    {\ifcsdef{columntype@\string#1}
      {\setbool{tpl@coltype@#1}{true}}%
      {\setbool{tpl@coltype@#1}{false}}%
    }%
}
\newcommand\IfColumntypeDefined[3]{%
  \CheckIfColumntypeDefined{#1}
  \ifboolexpr{ bool{tpl@coltype@#1} }{#2}{#3}%
}
\newcommand{\IfColumntypesDefined}[1]{%
  @tempswatrue
  \def\do##1{%
    % define @tempa with trimmed index element.
    \edef@tempa{\zap@space##1 @empty}%
    % check if package of current index is loaded
    \IfColumntypeDefined{@tempa}{}{@tempswafalse}%
  }%
  % Process csv list with command \do (etoolbox)
  \docsvlist{#1}%
  % ??
  \if@tempswa\expandafter@firstoftwo\else\expandafter@secondoftwo\fi%
}
\makeatother
\begin{document}
\newcolumntype{L}[1]{>{\RaggedRight\arraybackslash\hspace{0pt}}p{#1}}
\newcolumntype{C}[1]{>{\Centering\arraybackslash\hspace{0pt}}p{#1}}
\IfColumntypeDefined{L}{L is defined}{L is not defined}
\IfColumntypeDefined{C}{C is defined}{C is not defined}
\IfColumntypesDefined{L,C}
{L and C columns are defined}
{L and C columns are not defined}
\end{document}

It however returns always false which I do not understand and do not know how to debug. So the output is

L is deﬁned C is deﬁned

L and C columns are not deﬁned

score 1 · Accepted Answer · answered Dec 11 '11 at 15:23

I don't see any point in defining \IfColumntypesDefined with a list of column types; however the problem is in the

\IfColumntypeDefined{\@tempa}{}{\@tempswafalse}

line. With

\expandafter\IfColumntypeDefined\expandafter{\@tempa}{}{\@tempswafalse}

you get the correct result. The reason is that \string#1 is used in \CheckIfColumntypeDefined (which is a good thing, because it protects against wrong input).

Check if multiple column types are defined fails

1 Answers1