Implement the fc keyword and the \F string escape.

Along with the simple_casefolding and full_casefolding features.

fc() stands for foldcase, a sort of pseudo case (like lowercase),
which is used to implement Unicode casefolding. It maps a string
to a form where all case differences are erased, so it's a
locale-independent way of checking if two strings are the same,
regardless of case.

This functionality was, and still is, available through the
regular expression engine -- /i matches would use casefolding
internally. The fc keyword merely exposes this for easier access.

Previously, one could attempt to case-insensitively test two strings
for equality by doing

   lc($a) eq lc($b)

But that might get you wrong results, for example in the case of
\x{DF}, LATIN SMALL LETTER SHARP S.

1 files changed, 2 insertions, 1 deletions

diff --git a/opnames.h b/opnames.h
index 5d855ec447..8b6a39a161 100644
--- a/opnames.h
+++ b/opnames.h
@@ -387,10 +387,11 @@ typedef enum opcode {
 	OP_RVALUES	 = 370,
 	OP_COREARGS	 = 371,
 	OP_RUNCV	 = 372,
+	OP_FC		 = 373,
 	OP_max		
 } opcode;
 
-#define MAXO 373
+#define MAXO 374
 
 /* the OP_IS_* macros are optimized to a simple range check because
     all the member OPs are contiguous in regen/opcodes table.