Deprecate non-grapheme string delimiter

In order for Perl to eventually allow string delimiters to be Unicode
grapheme clusters (which look like a single character, but may be
multiple ones), we have to stop allowing a single char delimiter that
isn't a grapheme by itself.  These are unlikely to exist in actual code,
as they would typically display as attached to the character in front of
them, but we should be sure.

1 files changed, 7 insertions, 0 deletions

diff --git a/proto.h b/proto.h
index 3c3a6ce189..cc9a5840f5 100644
--- a/proto.h
+++ b/proto.h
@@ -5355,6 +5355,13 @@ STATIC void	S_to_utf8_substr(pTHX_ regexp * prog);
 #define PERL_ARGS_ASSERT_TO_UTF8_SUBSTR	\
 	assert(prog)
 #endif
+#if defined(PERL_IN_REGEXEC_C) || defined(PERL_IN_TOKE_C)
+PERL_CALLCONV bool	Perl__is_grapheme(pTHX_ const U8 * strbeg, const U8 * s, const U8 *strend, const UV cp)
+			__attribute__warn_unused_result__;
+#define PERL_ARGS_ASSERT__IS_GRAPHEME	\
+	assert(strbeg); assert(s); assert(strend)
+
+#endif
 #if defined(PERL_IN_REGEXEC_C) || defined(PERL_IN_UTF8_C)
 PERL_CALLCONV bool	Perl_isFOO_lc(pTHX_ const U8 classnum, const U8 character)
 			__attribute__warn_unused_result__;