[texhax] Query : why can \ifnum comparison operators not be \let, yet \def is OK ?
d.p.carlisle at gmail.com
Wed Feb 3 11:17:53 CET 2016
"Why?" is hard to answer. That is just how it is.
The comparison syntax needs an explicit < of catcode 12 but macros are
as usual expanded when tex is looking for syntactic forms, so it may
be produced by expanding \def defined macros.
The implicit < token defined by \let is a syntax error because it
isn't a catcode 12 token with character code of < > or =
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