Graphics, Figures & Tables ⇒ Float placement ignored when passed via macro

[woj-k]

Hello everyone,

I have come across an interesting problem with floats. As I was writing some wrapper environments, I noticed that the optional position argument cannot be processed correctly, if it is first stored and then retrieved from a temporary `storage' macro. In th MWE below, myfloatone ignores the position, and myfloattwo is fine with it. The only difference is how the optional argument is passed to the figure environment.

Code: Select all

\documentclass{article}

\newenvironment{myfloatone}[3][tbp]{%
\def\postemp{#1}\def\captemp{#2}\def\labtemp{#3}%
\begin{figure}[\postemp]}%          <- Difference here
{\caption{\captemp}\label{\labtemp}\end{figure}}

\newenvironment{myfloattwo}[3][tbp]{%
\def\postemp{#1}\def\captemp{#2}\def\labtemp{#3}%
\begin{figure}[#1]}%                <- Difference here
{\caption{\captemp}\label{\labtemp}\end{figure}}

\begin{document}
One

Two

\begin{myfloatone}[b]{caption one}{labelone}
\rule{1em}{1em}
\end{myfloatone}

Three

\clearpage
One

Two

\begin{myfloattwo}[b]{caption two}{labeltwo}
\rule{1em}{1em}\ \rule{1em}{1em}
\end{myfloattwo}

Three
\end{document}

Changing \def to \edef does nothing. The problem exists both when using latex and pdflatex.

Can anyone offer an explanation? And, more importantly, suggest how I could pass the position argument via another macro so that the float takes it in? Thank you in advance for any advice.

[cgnieder]

The macro in the option needs to be expanded before the table reads it. Maybe something like this can help:

Code: Select all

\documentclass{article}

\makeatletter
\def\ExpEnvOption#1#2[#3]{%
  \expandafter\@expenvopt\expandafter{#3}{#1}{#2}}
\def\@expenvopt#1#2#3{#2{#3}[#1]}
\makeatother

\def\options{h}

\begin{document}
text

\ExpEnvOption
\begin{table}[\options]
  table
\end{table}

text
\end{document}

Regards

[woj-k]

It worked! Your solution is trivially integrated into the MWE and solves the problem.

I would probably spend a good few more weeks fooling around with \expandafter's; switching arguments around and reading+inserting the square brackets in a separate step is a new trick to me. I will think on how to use it to my advantage in my existing code.

Thank you for your help!