X-Git-Url: http://git.shadowcat.co.uk/gitweb/gitweb.cgi?a=blobdiff_plain;f=lib%2FSwitch.pm;h=d7658bac8493a938111bf9f4a24a06c4401bbcdc;hb=a65cb92d1f93e8343c90e37bd9d70f91efe34546;hp=f709d9d7ba149c7be1fa549545cc7b62012667b7;hpb=8068f8fb8571bdb471f5f6ae0c96570a053c869b;p=p5sagit%2Fp5-mst-13.2.git diff --git a/lib/Switch.pm b/lib/Switch.pm index f709d9d..d7658ba 100644 --- a/lib/Switch.pm +++ b/lib/Switch.pm @@ -4,7 +4,7 @@ use strict; use vars qw($VERSION); use Carp; -$VERSION = '2.10'; +$VERSION = '2.13'; # LOAD FILTERING MODULE... @@ -48,7 +48,7 @@ sub filter local $Switch::file = (caller)[1]; my $status = 1; - $status = filter_read(10_000); + $status = filter_read(1_000_000); return $status if $status<0; $_ = filter_blocks($_,$offset); $_ = "# line $offset\n" . $_ if $offset; undef $offset; @@ -73,7 +73,7 @@ sub is_block } -my $EOP = qr/\n\n|\Z/; +my $EOP = qr/\n|\Z/; my $CUT = qr/\n=cut.*$EOP/; my $pod_or_DATA = qr/ ^=(?:head[1-4]|item) .*? $CUT | ^=pod .*? $CUT @@ -87,7 +87,7 @@ sub filter_blocks { my ($source, $line) = @_; return $source unless $Perl5 && $source =~ /case|switch/ - || $Perl6 && $source =~ /when|given/; + || $Perl6 && $source =~ /when|given|default/; pos $source = 0; my $text = ""; component: while (pos $source < length $source) @@ -100,8 +100,19 @@ sub filter_blocks my @pos = Text::Balanced::_match_quotelike(\$source,qr/\s*/,1,0); if (defined $pos[0]) { - $text .= " " if $pos[0] < $pos[2]; - $text .= substr($source,$pos[2],$pos[18]-$pos[2]); + my $pre = substr($source,$pos[0],$pos[1]); # matched prefix + my $iEol; + if( substr($source,$pos[4],$pos[5]) eq '/' && # 1st delimiter + substr($source,$pos[2],$pos[3]) eq '' && # no op like 'm' + index( substr($source,$pos[16],$pos[17]), 'x' ) == -1 && # no //x + ($iEol = index( $source, "\n", $pos[4] )) > 0 && + $iEol < $pos[8] ){ # embedded newlines + # If this is a pattern, it isn't compatible with Switch. Backup past 1st '/'. + pos( $source ) = $pos[6]; + $text .= $pre . substr($source,$pos[2],$pos[6]-$pos[2]); + } else { + $text .= $pre . substr($source,$pos[2],$pos[18]-$pos[2]); + } next component; } if ($source =~ m/\G\s*($pod_or_DATA)/gc) { @@ -121,7 +132,6 @@ sub filter_blocks { my $keyword = $3; my $arg = $4; - # print STDERR "[$arg]\n"; $text .= $1.$2.'S_W_I_T_C_H: while (1) '; unless ($arg) { @pos = Text::Balanced::_match_codeblock(\$source,qr/\s*/,qr/\(/,qr/\)/,qr/[[{(<]/,qr/[]})>]/,undef) @@ -144,11 +154,18 @@ sub filter_blocks next component; } elsif ($Perl5 && $source =~ m/\G(\s*)(case\b)(?!\s*=>)/gc - || $Perl6 && $source =~ m/\G(\s*)(when\b)(?!\s*=>)/gc) + || $Perl6 && $source =~ m/\G(\s*)(when\b)(?!\s*=>)/gc + || $Perl6 && $source =~ m/\G(\s*)(default\b)(?=\s*\{)/gc) { my $keyword = $2; - $text .= $1."if (Switch::case"; - if (@pos = Text::Balanced::_match_codeblock(\$source,qr/\s*/,qr/\{/,qr/\}/,qr/\{/,qr/\}/,undef)) { + $text .= $1 . ($keyword eq "default" + ? "if (1)" + : "if (Switch::case"); + + if ($keyword eq "default") { + # Nothing to do + } + elsif (@pos = Text::Balanced::_match_codeblock(\$source,qr/\s*/,qr/\{/,qr/\}/,qr/\{/,qr/\}/,undef)) { my $code = substr($source,$pos[0],$pos[4]-$pos[0]); $text .= " " if $pos[0] < $pos[2]; $text .= "sub " if is_block $code; @@ -496,26 +513,25 @@ Switch - A switch statement for Perl =head1 VERSION -This document describes version 2.09 of Switch, -released June 12, 2002. +This document describes version 2.11 of Switch, +released Nov 22, 2006. =head1 SYNOPSIS - use Switch; - - switch ($val) { - - case 1 { print "number 1" } - case "a" { print "string a" } - case [1..10,42] { print "number in list" } - case (@array) { print "number in list" } - case /\w+/ { print "pattern" } - case qr/\w+/ { print "pattern" } - case (%hash) { print "entry in hash" } - case (\%hash) { print "entry in hash" } - case (\&sub) { print "arg to subroutine" } - else { print "previous case not true" } - } + use Switch; + + switch ($val) { + case 1 { print "number 1" } + case "a" { print "string a" } + case [1..10,42] { print "number in list" } + case (@array) { print "number in list" } + case /\w+/ { print "pattern" } + case qr/\w+/ { print "pattern" } + case (%hash) { print "entry in hash" } + case (\%hash) { print "entry in hash" } + case (\&sub) { print "arg to subroutine" } + else { print "previous case not true" } + } =head1 BACKGROUND @@ -585,14 +601,11 @@ the existence of a series of keys (C{$c}>), one could test for the existence of a single key in a series of hashes (C{$s}>). -As L observes, a Perl case mechanism must support all these -"ways to do it". - - =head1 DESCRIPTION The Switch.pm module implements a generalized case mechanism that covers -the numerous possible combinations of switch and case values described above. +most (but not all) of the numerous possible combinations of switch and case +values described above. The module augments the standard Perl syntax with two new control statements: C and C. The C statement takes a @@ -632,23 +645,14 @@ mechanism: %special = ( woohoo => 1, d'oh => 1 ); while (<>) { + chomp; switch ($_) { - case (%special) { print "homer\n"; } # if $special{$_} - case /a-z/i { print "alpha\n"; } # if $_ =~ /a-z/i + case /[a-z]/i { print "alpha\n"; } # if $_ =~ /a-z/i case [1..9] { print "small num\n"; } # if $_ in [1..9] - - case { $_[0] >= 10 } { # if $_ >= 10 - my $age = <>; - switch (sub{ $_[0] < $age } ) { - - case 20 { print "teens\n"; } # if 20 < $age - case 30 { print "twenties\n"; } # if 30 < $age - else { print "history\n"; } - } - } - + case { $_[0] >= 10 } { print "big num\n"; } # if $_ >= 10 print "must be punctuation\n" case /\W/; # if $_ ~= /\W/ + } } Note that Ces can be nested within C (or any other) blocks, @@ -663,7 +667,7 @@ useful for aggregating integral cases: { switch ($_[0]) { case 0 { return 'zero' } case [2,4,6,8] { return 'even' } - case [1,3,4,7,9] { return 'odd' } + case [1,3,5,7,9] { return 'odd' } case /[A-F]/i { return 'hex' } } } @@ -675,7 +679,7 @@ Fall-though (trying another case after one has already succeeded) is usually a Bad Idea in a switch statement. However, this is Perl, not a police state, so there I a way to do it, if you must. -If a C block executes an untargetted C, control is +If a C block executes an untargeted C, control is immediately transferred to the statement I the C statement (i.e. usually another case), rather than out of the surrounding C block. @@ -692,7 +696,7 @@ For example: If $val held the number C<1>, the above C block would call the first three C subroutines, jumping to the next case test -each time it encountered a C. After the thrid C block +each time it encountered a C. After the third C block was executed, control would jump to the end of the enclosing C block. @@ -707,7 +711,7 @@ For example: case /\d/ { handle_dig_any(); } } -If an untargetted C statement is executed in a case block, this +If an untargeted C statement is executed in a case block, this immediately transfers control out of the enclosing C block (in other words, there is an implicit C at the end of each normal C block). Thus the previous example could also have been @@ -761,6 +765,7 @@ importing it with the argument C<"Perl6">. For example: when [0..9] { handle_num_any(); last } when /\d/ { handle_dig_any(); } when /.*/ { handle_str_any(); } + default { handle anything else; } } Note that scalars still need to be parenthesized, since they would be @@ -780,17 +785,19 @@ be tested against a series of conditions. For example: sub beverage { switch (shift) { - - case sub { $_[0] < 10 } { return 'milk' } - case sub { $_[0] < 20 } { return 'coke' } - case sub { $_[0] < 30 } { return 'beer' } - case sub { $_[0] < 40 } { return 'wine' } - case sub { $_[0] < 50 } { return 'malt' } - case sub { $_[0] < 60 } { return 'Moet' } - else { return 'milk' } + case { $_[0] < 10 } { return 'milk' } + case { $_[0] < 20 } { return 'coke' } + case { $_[0] < 30 } { return 'beer' } + case { $_[0] < 40 } { return 'wine' } + case { $_[0] < 50 } { return 'malt' } + case { $_[0] < 60 } { return 'Moet' } + else { return 'milk' } } } +(This is equivalent to writing C, etc.; C<$_[0]> +is the argument to the anonymous subroutine.) + The need to specify each condition as a subroutine block is tiresome. To overcome this, when importing Switch.pm, a special "placeholder" subroutine named C<__> [sic] may also be imported. This subroutine @@ -799,11 +806,11 @@ higher-order function. That is, the expression: use Switch '__'; - __ < 2 + __ + __ < 2 is equivalent to: - sub { $_[0] < 2 + $_[1] } + sub { $_[0] < 2 } With C<__>, the previous ugly case statements can be rewritten: @@ -843,21 +850,34 @@ and requires both these modules to be installed. =head1 AUTHOR -Damian Conway (damian@conway.org) +Damian Conway (damian@conway.org). The maintainer of this module is now Rafael +Garcia-Suarez (rgarciasuarez@gmail.com). =head1 BUGS There are undoubtedly serious bugs lurking somewhere in code this funky :-) Bug reports and other feedback are most welcome. -=head1 LIMITATION +=head1 LIMITATIONS -Due to the heuristic nature of Switch.pm's source parsing, the presence +Due to the heuristic nature of Switch.pm's source parsing, the presence of +regexes with embedded newlines that are specified with raw C +delimiters and don't have a modifier C are indistinguishable from +code chunks beginning with the division operator C. As a workaround +you must use C or C for such patterns. Also, the presence of regexes specified with raw C delimiters may cause mysterious errors. The workaround is to use C instead. +Due to the way source filters work in Perl, you can't use Switch inside +an string C. + +If your source file is longer then 1 million characters and you have a +switch statement that crosses the 1 million (or 2 million, etc.) +character boundary you will get mysterious errors. The workaround is to +use smaller source files. + =head1 COPYRIGHT - Copyright (c) 1997-2001, Damian Conway. All Rights Reserved. + Copyright (c) 1997-2006, Damian Conway. All Rights Reserved. This module is free software. It may be used, redistributed and/or modified under the same terms as Perl itself.