Re: Case-sensitive support with regexp specials ?

[Richard Stallman]

    Yuck: IMHO a balanced syntax like \(?:...\) would be better than a
           state-switching construction.

For this operation, requiring "balance" might make it clumsy and could
also interfere with use.  I think the syntax of \c and \C fits in
better.

However, \c and \C already have meanings in Emacs regexps, for
matching in terms of character categories.  So we would need to choose
some other letter for this, or else change incompatibly to a different
letter for categories.  (Such an incompatible change would not be
tragic, since users probably don't use the syntax very much.)