[texhax] macro expansion and \input

[Philip TAYLOR]

Neal H. Walfield wrote:

> Based on this observation, I tried to preexpand \input's argument:
>
>    \documentclass{article}
>
>    \begin{document}
>
>    % My general-purpose macro.
>    \def\mutate#1{
>      \def\helper{#1}
>      \helper
>    }
>
>    \def\myinput#1{
>      \edef\filename{#1}
>      \input{\filename}
>    }
>
>    \myinput{\mutate{23}}
>
>    \end{document}
>
> But, this results in a different error:

Neal, as you do not give us any information as to exactly how
you want to mutate the filename, I cannot be certain that the
following will work, but for my simple version which just
prepends the letter "X" it seems adequate.  It is based
on your \myinput, but puts /all/ of the functionality there
rather than requiring \mutate to be passed as a part of
the parameter string.

Philip Taylor
--------
   \documentclass {minimal}

   \begin{document}

   \def \mutate #1{X#1}
   \def \myinput #1%
   {
     \edef \filename {\mutate {#1}}%
     \input {\filename}%
   }

   \myinput{23}}

   \end{document}