Re: regexp case sensitivity bug

[David Kastrup <David.Kastrup@t-online.de>]

Dean Herington <heringto@cs.unc.edu> writes:

> In Emacs 21.1.1, when I do isearch-forward-regexp with input "\bP",
> Emacs matches 'p's case insensitively.  I see nothing in the
> documentation to suggest that the case sensitivity behavior should
> differ from that of isearch-forward, where "P" matches only upper-case
> 'p's.

But I see something in the documentation:

File: emacs,  Node: Search Case,  Next: Replace,  Prev: Regexps,  Up: Search

Searching and Case
==================

   Incremental searches in Emacs normally ignore the case of the text
they are searching through, if you specify the text in lower case.
Thus, if you specify searching for `foo', then `Foo' and `foo' are also
considered a match.  Regexps, and in particular character sets, are
included: `[ab]' would match `a' or `A' or `b' or `B'.

   An upper-case letter anywhere in the incremental search string makes
the search case-sensitive.  Thus, searching for `Foo' does not find
`foo' or `FOO'.  This applies to regular expression search as well as
to string search.  The effect ceases if you delete the upper-case
letter from the search string.

   Typing `M-c' within an incremental search toggles the case
sensitivity of that search.  The effect does not extend beyond the
current incremental search to the next one, but it does override the
effect of including an upper-case letter in the current search.

   If you set the variable `case-fold-search' to `nil', then all
letters must match exactly, including case.  This is a per-buffer
variable; altering the variable affects only the current buffer, but
there is a default value which you can change as well.  See *Note Locals::.
This variable applies to nonincremental searches also, including those
performed by the replace commands (see *note Replace::) and the minibuffer
history matching commands (see *note Minibuffer History::).

-- 
David Kastrup, Kriemhildstr. 15, 44793 Bochum