Re: re-search bug?

[Richard Stallman]

    That's what I would expect.  I think even the definition of "case fold
    search" is not as obvious as it seems.  Does it mean (equal (upcase X)
    (upcase Y)) or (equal (downcase X) (downcase Y)) or something yet different?

Neither of those.  It is supposed to find matches whenever the
characters are connected by any sequence of case conversions.  This
uses the canon table and the equiv table.  In search_buffer and its
subroutines, TRT refers to the canon table, and INVERSE_TRT refers to
the equiv table.  So the table passed to regex searching is the canon
table.

Definitions of these two tables:

CANONICALIZE maps each character to a canonical equivalent;
 any two characters that are related by case-conversion have the same
 canonical equivalent character...
EQUIVALENCES is a map that cyclicly permutes each equivalence class
 (of characters with the same canonical equivalent)...

A good first step would be to look at the canon and equiv table
contents, in the case that fails, and see if they correspond correctly
to the upcase and downcase tables.