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author | ph10 <ph10@2f5784b3-3f2a-0410-8824-cb99058d5e15> | 2009-10-04 09:27:20 +0000 |
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committer | ph10 <ph10@2f5784b3-3f2a-0410-8824-cb99058d5e15> | 2009-10-04 09:27:20 +0000 |
commit | 7f1b753dfecb0db660812f00e667abaca6252e28 (patch) | |
tree | aa5a0541136555a21f47051e4c78c591b969f4fc /HACKING | |
parent | ff6ca31f93c0b34a945871afc954a0aa54800137 (diff) | |
download | pcre-7f1b753dfecb0db660812f00e667abaca6252e28.tar.gz |
Documentation update.
git-svn-id: svn://vcs.exim.org/pcre/code/trunk@460 2f5784b3-3f2a-0410-8824-cb99058d5e15
Diffstat (limited to 'HACKING')
-rw-r--r-- | HACKING | 15 |
1 files changed, 9 insertions, 6 deletions
@@ -373,12 +373,15 @@ These are like other subpatterns, but they start with the opcode OP_COND, or 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 |