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| author | John Tobey <jtobey@john-edwin-tobey.org> | 1998-11-19 09:14:15 -0500 |
|---|---|---|
| committer | Gurusamy Sarathy <gsar@cpan.org> | 1998-11-28 18:08:50 +0000 |
| commit | 19ddd453f2e40b974c6259d7b47fde33e9f744b5 (patch) | |
| tree | 3713c7b43705a8b722b441ba9cc52017e432ae29 /pod/perlvar.pod | |
| parent | df4a00a5f8fe391f745418d99ee82968fe9faa58 (diff) | |
| download | perl-19ddd453f2e40b974c6259d7b47fde33e9f744b5.tar.gz | |
PATCH: document English.pm sawampersand and thread issues
Message-Id: <m0zgZWx-000FOgC@feynman.localnet>
p4raw-id: //depot/perl@2362
Diffstat (limited to 'pod/perlvar.pod')
| -rw-r--r-- | pod/perlvar.pod | 21 |
1 files changed, 21 insertions, 0 deletions
diff --git a/pod/perlvar.pod b/pod/perlvar.pod index 38fd1684ee..7100af5b75 100644 --- a/pod/perlvar.pod +++ b/pod/perlvar.pod @@ -17,6 +17,15 @@ at the top of your program. This will alias all the short names to the long names in the current package. Some even have medium names, generally borrowed from B<awk>. +Due to an unfortunate accident of Perl's implementation, "C<use English>" +imposes a considerable performance penalty on all regular expression +matches in a program, regardless of whether they occur in the scope of +"C<use English>". For that reason, saying "C<use English>" in +libraries is strongly discouraged. See the Devel::SawAmpersand module +documentation from CPAN +(http://www.perl.com/CPAN/modules/by-module/Devel/Devel-SawAmpersand-0.10.readme) +for more information. + To go a step further, those variables that depend on the currently selected filehandle may instead (and preferably) be set by calling an object method on the FileHandle object. (Summary lines below for this @@ -127,6 +136,10 @@ The string matched by the last successful pattern match (not counting any matches hidden within a BLOCK or eval() enclosed by the current BLOCK). (Mnemonic: like & in some editors.) This variable is read-only. +The use of this variable anywhere in a program imposes a considerable +performance penalty on all regular expression matches. See the +Devel::SawAmpersand module from CPAN for more information. + =item $PREMATCH =item $` @@ -136,6 +149,10 @@ pattern match (not counting any matches hidden within a BLOCK or eval enclosed by the current BLOCK). (Mnemonic: C<`> often precedes a quoted string.) This variable is read-only. +The use of this variable anywhere in a program imposes a considerable +performance penalty on all regular expression matches. See the +Devel::SawAmpersand module from CPAN for more information. + =item $POSTMATCH =item $' @@ -151,6 +168,10 @@ string.) Example: This variable is read-only. +The use of this variable anywhere in a program imposes a considerable +performance penalty on all regular expression matches. See the +Devel::SawAmpersand module from CPAN for more information. + =item $LAST_PAREN_MATCH =item $+ |