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I have a macro that is repeatedly called in my document

\newcommand\foo[1]{Process #1}
\newcommand\var[2]{Do something with #1 and #2, and then call '\foo{#2}', and again '\foo{#2}', and once again '\foo{#2}'}

The macro foo is expanded many times inside var with the same argument, one may think that passing the argument is just redundant, and could be possibly avoided.

Question: Is it possible to have a version of foo such that when var is defined as

\newcommand\var[2]{Do something with #1 and #2, and then call '\foo', and again '\foo', and once again '\foo'}

would lead to the result of the first example?

MWE

\documentclass[]{article}

\newcommand\foo[1]{Process #1}
\newcommand\var[2]{Do something with #1 and #2, and then call '\foo{#2}', and again '\foo{#2}', and once again '\foo{#2}'}

\begin{document}

\var{x}{y}

\end{document}

And this is the output enter image description here

I would like to have the same result, after defining var as

\newcommand\var[2]{Do something with #1 and #2, and then call '\foo', and again '\foo', and once again '\foo'}
8
  • Could you please provide a small minimum working example, for us to better see what you are trying to accomplish? Commented Apr 30, 2018 at 13:40
  • @StevenB.Segletes Absolutely, I just added it
    – caverac
    Commented Apr 30, 2018 at 13:47
  • @marmot Do you mean something like \newcommand\foo{Process \noexpand{#1}}? It doesn't work, right? I've try a bunch of combinations of edefs and \expandafters but I cannot make it work
    – caverac
    Commented Apr 30, 2018 at 13:48
  • 2
    Something close: \renewcommand\var[2]{\def\foo{Process #2}Do something with #1 and #2, and then call '\foo', and again '\foo', and once again '\foo'} Commented Apr 30, 2018 at 14:14
  • 1
    @StevenB.Segletes I see, thanks for your time. If you add these comments as an answer I will gladly accept it
    – caverac
    Commented Apr 30, 2018 at 23:31

1 Answer 1

2

The OP asked me to convert comments into an answer. None of which give exactly what the OP was hoping for.

The problem is that I see no way to get #2 or its equivalent value into \foo without doing something with #2 to save it somewhere. But that can only occur after \var is invoked or via some pre-\var macro invocation.

I show both these alternatives in the MWE below.

\documentclass[]{article}
\begin{document}
Original approach of OP

\newcommand\foo[1]{Process #1}
\newcommand\var[2]{Do something with #1 and #2, and then call '\foo{#2}', and again '\foo{#2}', and once again '\foo{#2}'}

\var{x}{y}

\hrulefill

Requires a leading \verb|\def| inside of \verb|\var|

\renewcommand\var[2]{\def\foo{Process #2}Do something with #1 and #2, and then call '\foo', and again '\foo', and once again '\foo'}

\var{x}{y}

\hrulefill

Defines \verb|\var| as desired, but requires invocation of \verb|\setvar|

\renewcommand\var[2]{Do something with #1 and #2, and then call '\foo', and again '\foo', and once again '\foo'}

\newcommand\setvar[2]{\def\foo{Process #2}\var{#1}{#2}}

\setvar{x}{y}
\end{document}

enter image description here

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