How to escape /None in \foreach iterator?

Question

The last compiler to invoke is

ps2pdf -dAutoRotatePages#/None frames.ps

for Windows or

ps2pdf -dAutoRotatePages=/None frames.ps

for non-Windows.

The code snippet I want to invoke is as follows.

\foreach \compiler/\ext in {latex/tex,dvips/dvi,ps2pdf -dAutoRotatePages#/None/ps}
    {\immediate\write18{\compiler\space frames.\ext}}

But if you need the complete code, see my last answer here.

Probably the iterator gets confused with /None because / is used for the delimiter. How to escape /None?

Answer 1

You don't want to only escape /None, but also # that's illegal in that context:

\edef\hms{\string#/}% Hash Mark Slash
\foreach \compiler/\ext in {latex/tex,dvips/dvi,ps2pdf -dAutoRotatePages\hms None/ps}
    {\immediate\write18{\compiler\space frames.\ext}}

The variant you mentioned in chat is even better:

\edef\AutoRotateOff{-dAutoRotatePages\string#/None}
\foreach \compiler/\ext in {latex/tex,dvips/dvi,ps2pdf \AutoRotateOff/ps}
    {\immediate\write18{\compiler\space frames.\ext}}

Both exploit the fact that \write fully expands its argument.

Another variant:

\makeatletter
\foreach \compiler/\ext in {latex/tex,dvips/dvi,%
  \@firstofone{ps2pdf -dAutoRotatePages\string#/None}/ps}
    {\immediate\write18{\compiler\space frames.\ext}}
\makeatother

Answer 2

Based on @egreg's answer, the / can be removed from \hms but we need {...} for ps2pdf item as follows.

\edef\hms{\string#}

\foreach \compiler/\ext in {latex/tex,dvips/dvi,{ps2pdf -dAutoRotatePages\hms/None}/ps}{\immediate\write18{\compiler\space temporary.\ext}}

MWE

% this input file name is filename.tex
% compile it with pdflatex -shell-escape filename.tex

\documentclass[preview,border=12pt]{standalone}

\usepackage{filecontents}

\begin{filecontents*}{temporary.tex}
\documentclass[pstricks,border=12pt]{standalone}
\begin{document}
\begin{pspicture}(4,2)
    \rput{90}(2,1){Marienplatz}
\end{pspicture}
\end{document}
\end{filecontents*}


\usepackage{graphicx,pgffor}
\edef\hms{\string#}

\foreach \compiler/\ext in {latex/tex,dvips/dvi,{ps2pdf -dAutoRotatePages\hms/None}/ps}{\immediate\write18{\compiler\space temporary.\ext}}

\begin{document}
\includegraphics{temporary}
\end{document}

More about Windows

In my experience with Windows 7, both -dAutoRotatePages=/None and -dAutoRotatePages#/None work on Windows. Therefore, the simplest solution just needs {...} as follows.

% this input file name is filename.tex
% compile it with pdflatex -shell-escape filename.tex

\documentclass[preview,border=12pt]{standalone}

\usepackage{filecontents}

\begin{filecontents*}{temporary.tex}
\documentclass[pstricks,border=12pt]{standalone}
\begin{document}
\begin{pspicture}(4,2)
    \rput{90}(2,1){Marienplatz}
\end{pspicture}
\end{document}
\end{filecontents*}


\usepackage{graphicx,pgffor}

\foreach \compiler/\ext in {latex/tex,dvips/dvi,{ps2pdf -dAutoRotatePages=/None}/ps}{\immediate\write18{\compiler\space temporary.\ext}}

\begin{document}
\includegraphics{temporary}
\end{document}

Warning

Don't replace \string# with \# as \# will not work (I just tried it).

Answer 3

edit (2017): since xint 1.1 (2014/10/28) one needed here \usepackage{xinttools}, not \usepackage{xint}.

As \xintForpair does not use / it is possible to have a simpler syntax:

% this input file name is filename.tex
% compile it with pdflatex -shell-escape filename.tex

\documentclass[preview,border=12pt]{standalone}
\usepackage{filecontents}

\begin{filecontents*}{temporary.tex}
\documentclass[pstricks,border=12pt]{standalone}
\begin{document}
\begin{pspicture}(4,2)
    \rput{90}(2,1){Marienplatz}
\end{pspicture}
\end{document}
\end{filecontents*}


\usepackage{graphicx}
\usepackage{xinttools}

\xintForpair #1#2 in 
   {(latex,tex),(dvips,dvi),(ps2pdf -dAutoRotatePages\string#/None,ps)}
\do {\immediate\write18{#1 temporary.#2}}

\begin{document}
\includegraphics{temporary}
\end{document}

Latest version of xint transparently removes spaces in comma separated lists, so the above may have all the additional spaces you desire around commas and parentheses.