🚀 go-pugleaf

bbeeton wrote on 09 January 1993:
 >julio dix (jd01@swtexas.bitnet, to comp.text.tex, jan 8) wants
 >to strip off the first digit from a series of digits in a box,
 >replacing the remaining digits into the same box.
 >
 >i won't tackle the boxing part of the question, but can explain
 >why the whole string of numbers is being gobbled at once.
 >
 >take a simpler example:
 >    \newcount\num
 >    \def\newnum#1#2.{\num=#1 \def\rest{#2}}
 >    \newnum12345.
 >this will end up with \num=12345 and \rest empty (with a delimited
 >string, the part between delimiters need not contain anything).

I'm afraid this is incorrect. If you run the above commands and use
\showthe\num and \show\rest you'll see that \num is indeed 1 and \rest is 2345.
The reason is that the definition of an argument is independent of the
replacement text of the macro.

Carlos