Unicode: add ToFold mapping. Not used yet; but basically

a more useful mapping for caseless aka case-ignoring than
doing either lc($a) eq lc($b) or uc($a) eq uc($b); the full
algorithm for creating the foldings uses equivalence classes,
see http://www.unicode.org/unicode/reports/tr21/
Hopefully this feature will be used in //i.
(The folding tables were introduced by #12689.)

p4raw-id: //depot/perl@12807

1 files changed, 10 insertions, 3 deletions

diff --git a/utf8.c b/utf8.c
index ac90a38283..768db078b8 100644
--- a/utf8.c
+++ b/utf8.c
@@ -1223,21 +1223,28 @@ UV
 Perl_to_utf8_upper(pTHX_ U8 *p, U8* ustrp, STRLEN *lenp)
 {
     return Perl_to_utf8_case(aTHX_ p, ustrp, lenp,
-			     &PL_utf8_toupper, "ToUpper", "utf8::ToSpecUpper");
+                             &PL_utf8_toupper, "ToUpper", "utf8::ToSpecUpper");
 }
 
 UV
 Perl_to_utf8_title(pTHX_ U8 *p, U8* ustrp, STRLEN *lenp)
 {
     return Perl_to_utf8_case(aTHX_ p, ustrp, lenp,
-			     &PL_utf8_totitle, "ToTitle", "utf8::ToSpecTitle");
+                             &PL_utf8_totitle, "ToTitle", "utf8::ToSpecTitle");
 }
 
 UV
 Perl_to_utf8_lower(pTHX_ U8 *p, U8* ustrp, STRLEN *lenp)
 {
     return Perl_to_utf8_case(aTHX_ p, ustrp, lenp,
-			     &PL_utf8_tolower, "ToLower", "utf8::ToSpecLower");
+                             &PL_utf8_tolower, "ToLower", "utf8::ToSpecLower");
+}
+
+UV
+Perl_to_utf8_fold(pTHX_ U8 *p, U8* ustrp, STRLEN *lenp)
+{
+    return Perl_to_utf8_case(aTHX_ p, ustrp, lenp,
+                             &PL_utf8_tofold, "ToFold", "utf8::ToSpecFold");
 }
 
 /* a "swash" is a swatch hash */