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| author | ph10 <ph10@6239d852-aaf2-0410-a92c-79f79f948069> | 2019-07-28 15:32:11 +0000 |
|---|---|---|
| committer | ph10 <ph10@6239d852-aaf2-0410-a92c-79f79f948069> | 2019-07-28 15:32:11 +0000 |
| commit | a0ec5a230a71ab8d870190c6153dc540d0885f67 (patch) | |
| tree | 6e85c954edaa9a2d8275ad3df3872a4044e221ec /doc/pcre2.txt | |
| parent | fc594b674bafcc3c9b12274bdb4faed9d36853b0 (diff) | |
| download | pcre2-a0ec5a230a71ab8d870190c6153dc540d0885f67.tar.gz | |
Documentation and test update.
git-svn-id: svn://vcs.exim.org/pcre2/code/trunk@1145 6239d852-aaf2-0410-a92c-79f79f948069
Diffstat (limited to 'doc/pcre2.txt')
| -rw-r--r-- | doc/pcre2.txt | 20 |
1 files changed, 14 insertions, 6 deletions
diff --git a/doc/pcre2.txt b/doc/pcre2.txt index 5722184..f662610 100644 --- a/doc/pcre2.txt +++ b/doc/pcre2.txt @@ -9439,11 +9439,19 @@ BACKTRACKING CONTROL substrings are retained in both cases. The remaining verbs act only when a later failure causes a backtrack to - reach them. This means that their effect is confined to the assertion, - because lookaround assertions are atomic. A backtrack that occurs after - an assertion is complete does not jump back into the assertion. Note in - particular that a (*MARK) name that is set in an assertion is not - "seen" by an instance of (*SKIP:NAME) latter in the pattern. + reach them. This means that, for the Perl-compatible assertions, their + effect is confined to the assertion, because Perl lookaround assertions + are atomic. A backtrack that occurs after such an assertion is complete + does not jump back into the assertion. Note in particular that a + (*MARK) name that is set in an assertion is not "seen" by an instance + of (*SKIP:NAME) later in the pattern. + + PCRE2 now supports non-atomic positive assertions, as described in the + section entitled "Non-atomic assertions" above. These assertions must + be standalone (not used as conditions). They are not Perl-compatible. + For these assertions, a later backtrack does jump back into the asser- + tion, and therefore verbs such as (*COMMIT) can be triggered by back- + tracks from later in the pattern. The effect of (*THEN) is not allowed to escape beyond an assertion. If there are no more branches to try, (*THEN) causes a positive assertion @@ -9494,7 +9502,7 @@ AUTHOR REVISION - Last updated: 13 July 2019 + Last updated: 28 July 2019 Copyright (c) 1997-2019 University of Cambridge. ------------------------------------------------------------------------------ |