Subject: bug#18018: 24.4.50; (emacs) `Special Isearch'

From: Michael Heerdegen <[email-masked]>
Date: Sun, 01 May 2016 01:12:17 +0200

Drew Adams <[email-masked]> writes:

> Really?  I don't have a build more recent than 2015-12-10, but in that
> build, at least, the identical text is still there, and I see nothing
> added about this being only the default behavior or about
> `case-fold-search'.
>
> But if this was really fixed, great.

Seems this has been fixed when the new char folding stuff has been
integrated.  Now the relevant text is in (info "(emacs) Lax Search") and
reads like:

   Searches in Emacs by default ignore the case of the text they are
searching through, if you specify the search string in lower case.
Thus, if you specify searching for ‘foo’, then ‘Foo’ and ‘foo’ also
match.  Regexps, and in particular character sets, behave likewise:
‘[ab]’ matches ‘a’ or ‘A’ or ‘b’ or ‘B’.  This feature is known as “case
folding”, and it is supported in both incremental and non-incremental
search modes.

   An upper-case letter anywhere in the 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 literal string
search.  The effect ceases if you delete the upper-case letter from the
search string.  The variable ‘search-upper-case’ controls this: if it is
non-‘nil’ (the default), an upper-case character in the search string
make the search case-sensitive; setting it to ‘nil’ disables this effect
of upper-case characters.

   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 normally affects only the current buffer, unless
you change its default value.  *Note Locals::.  This variable applies to
nonincremental searches also, including those performed by the replace
commands (*note Replace::) and the minibuffer history matching commands
(*note Minibuffer History::).

   Typing ‘M-c’ or ‘M-s c’ (‘isearch-toggle-case-fold’) within an
incremental search toggles the case sensitivity of that search.  The
effect does not extend beyond the current incremental search, but it
does override the effect of adding or removing an upper-case letter in
the current search.

[...]

Michael.