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Consider the following:

\let\1=X
\edef\2{\1}
\show\1 \show\2

The result is 

> \1=the letter X.

> \2=macro:
->\1.

Is it possible to ‘expand’ the meaning of \1 so that \2 contains just X? The only solution I can think of is to use \meaning on \1 and cut out the prefix, but that doesn't seem very elegant.

(Context: I'm writing a scanning function that looks ahead at the next token and then either adds it to a scratch variable or terminates the scanning. Can't add it to the scratch variable without expanding it first, though! But it's not the context that I care about, since I can do the loop in another way; I'm interested in this particular question.)

lockstep
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Will Robertson
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  • Maybe we should ask Taco to add such a function to the token library. – Philipp Dec 24 '10 at 12:21
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    Please make this site more user friendly! I wanted to comment (actually ask a question) on Joseph's answer, but I couldn't. – Ahmed Musa Jan 08 '11 at 22:07
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1 Answers1

10

You can't expand a token which has been defined using \let (unless of course we are taking about something \let to another macro). As you say, \meaning is the only way that is going to work. Sorry if this is something of a non-answer!

Joseph Wright
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