Hi Arash,

Thanks, that clarifies things.

To give an example, suppose we wanted to fold your \Verb macro.  To do
so, we might try adding

  ("{1}" ("lVerb"))

to TeX-fold-macro-spec-list.  Folding then fails because, with point
at the start of "\Verb",

  (TeX-fold-macro-nth-arg 1 (point))

returns nil, but should return a string with contents "foo@bar".

The function LaTeX-verbatim-macro-boundaries that you mentioned leads
to a workaround: if we tweak TeX-fold-macro-nth-arg as in the attached
(incomplete) patch and add

  (my-display ("Verb"))

to TeX-fold-macro-spec-list, where

  (defun my-display (text &rest args) text)

then folding of \Verb{...} works as intended.  We would need to tweak
TeX-fold-macro-nth-arg further (and probably make it look a bit hacky)
to get it to work correctly with ("{1}" ("lVerb")), however.  Any
suggestions would be welcome.

Thanks, best,

Paul