"Neal H. Walfield" <neal at walfield.org> a écrit:
>
> Hi,
>
> I have a large \def that takes some parameters. I want to define a
> convenience macro, which I use from my outer definition, and which
> also takes parameters. Consider:
>
> \documentclass{article}
>
> \begin{document}
>
> \def\foo#1{%
> \def\bar#1{%
> xxx #1 yyy%
> }%
> \bar{aaa #1 bbb}%
> }
>
> \foo{!}
>
> \end{document}
>
> When I compile this, I get:
>
> ! Use of \bar doesn't match its definition.
> \foo #1->\def \bar #1{xxx #1 yyy}\bar {
> aaa #1 bbb}
> l.12 \foo{!}
>
> This is because the #1 in the \bar definition is expanded to the value
> of the argument passed to \foo. How do I escape the #1 in bar's
> definition? What are good approaches to do this type of thing?
In the body of a definition (its replacement text), to denote a #, you
should double it: ##. So, in your case the definition is:
\def\foo#1{%
\def\bar##1{%
xxx ##1 yyy%
}%
\bar{aaa #1 bbb}%
}
If \bar iself defined another macro with parameter text, the latter
should use four #'s per argument, and so on.
Best,
Paul