Revision: 460
http://vcs.pcre.org/viewvc?view=rev&revision=460
Author: ph10
Date: 2009-10-04 10:27:20 +0100 (Sun, 04 Oct 2009)
Log Message:
-----------
Documentation update.
Modified Paths:
--------------
code/trunk/HACKING
Modified: code/trunk/HACKING
===================================================================
--- code/trunk/HACKING 2009-10-04 09:21:39 UTC (rev 459)
+++ code/trunk/HACKING 2009-10-04 09:27:20 UTC (rev 460)
@@ -373,14 +373,17 @@
OP_SCOND for one that might match an empty string in an unbounded repeat. If
the condition is a back reference, this is stored at the start of the
subpattern using the opcode OP_CREF followed by two bytes containing the
-reference number. If the condition is "in recursion" (coded as "(?(R)"), or "in
-recursion of group x" (coded as "(?(Rx)"), the group number is stored at the
-start of the subpattern using the opcode OP_RREF, and a value of zero for "the
-whole pattern". For a DEFINE condition, just the single byte OP_DEF is used (it
-has no associated data). Otherwise, a conditional subpattern always starts with
-one of the assertions.
+reference number. OP_NCREF is used instead if the reference was generated by
+name (so that the runtime code knows to check for duplicate names).
+If the condition is "in recursion" (coded as "(?(R)"), or "in recursion of
+group x" (coded as "(?(Rx)"), the group number is stored at the start of the
+subpattern using the opcode OP_RREF or OP_NRREF (cf OP_NCREF), and a value of
+zero for "the whole pattern". For a DEFINE condition, just the single byte
+OP_DEF is used (it has no associated data). Otherwise, a conditional subpattern
+always starts with one of the assertions.
+
Recursion
---------
