diff options
Diffstat (limited to 'lib/English.pm')
| -rw-r--r-- | lib/English.pm | 54 |
1 files changed, 42 insertions, 12 deletions
diff --git a/lib/English.pm b/lib/English.pm index f38c313beb..1ebc3de11d 100644 --- a/lib/English.pm +++ b/lib/English.pm @@ -9,6 +9,7 @@ English - use nice English (or awk) names for ugly punctuation variables =head1 SYNOPSIS + use English qw( -no_match_vars ) ; # Avoids regex performance penalty use English; ... if ($ERRNO =~ /denied/) { ... } @@ -27,29 +28,52 @@ $INPUT_RECORD_SEPARATOR if you are using the English module. See L<perlvar> for a complete list of these. -=head1 BUGS +=head1 PERFORMANCE -This module provokes sizeable inefficiencies for regular expressions, -due to unfortunate implementation details. If performance matters, -consider avoiding English. +This module can provoke sizeable inefficiencies for regular expressions, +due to unfortunate implementation details. If performance matters in +your application and you don't need $PREMATCH, $MATCH, or $POSTMATCH, +try doing + + use English qw( -no_match_vars ) ; + +. B<It is especially important to do this in modules to avoid penalizing +all applications which use them.> =cut no warnings; +my $globbed_match ; + # Grandfather $NAME import sub import { my $this = shift; - my @list = @_; + my @list = grep { ! /^-no_match_vars$/ } @_ ; local $Exporter::ExportLevel = 1; + if ( @_ == @list ) { + *EXPORT = \@COMPLETE_EXPORT ; + $globbed_match ||= ( + eval q{ + *MATCH = *& ; + *PREMATCH = *` ; + *POSTMATCH = *' ; + 1 ; + } + || do { + require Carp ; + Carp::croak "Can't create English for match leftovers: $@" ; + } + ) ; + } + else { + *EXPORT = \@MINIMAL_EXPORT ; + } Exporter::import($this,grep {s/^\$/*/} @list); } -@EXPORT = qw( +@MINIMAL_EXPORT = qw( *ARG - *MATCH - *PREMATCH - *POSTMATCH *LAST_PAREN_MATCH *INPUT_LINE_NUMBER *NR @@ -102,15 +126,21 @@ sub import { @LAST_MATCH_END ); + +@MATCH_EXPORT = qw( + *MATCH + *PREMATCH + *POSTMATCH +); + +@COMPLETE_EXPORT = ( @MINIMAL_EXPORT, @MATCH_EXPORT ) ; + # The ground of all being. @ARG is deprecated (5.005 makes @_ lexical) *ARG = *_ ; # Matching. - *MATCH = *& ; - *PREMATCH = *` ; - *POSTMATCH = *' ; *LAST_PAREN_MATCH = *+ ; *LAST_MATCH_START = *-{ARRAY} ; *LAST_MATCH_END = *+{ARRAY} ; |