use vars qw($VERSION);
use Carp;
-$VERSION = '2.10';
+use if $] >= 5.011, 'deprecate';
+$VERSION = '2.14_01';
+
# LOAD FILTERING MODULE...
use Filter::Util::Call;
return !$ishash;
}
-
-my $EOP = qr/\n\n|\Z/;
-my $CUT = qr/\n=cut.*$EOP/;
-my $pod_or_DATA = qr/ ^=(?:head[1-4]|item) .*? $CUT
- | ^=pod .*? $CUT
- | ^=for .*? $EOP
- | ^=begin \s* (\S+) .*? \n=end \s* \1 .*? $EOP
- | ^__(DATA|END)__\n.*
- /smx;
+my $pod_or_DATA = qr/ ^=[A-Za-z] .*? ^=cut (?![A-Za-z]) .*? $
+ | ^__(DATA|END)__\n.*
+ /smx;
my $casecounter = 1;
sub filter_blocks
if (defined $pos[0])
{
my $pre = substr($source,$pos[0],$pos[1]); # matched prefix
- $text .= $pre . substr($source,$pos[2],$pos[18]-$pos[2]);
+ 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*($pod_or_DATA)/gc) {
+ if ($source =~ m/(\G\s*$pod_or_DATA)/gc) {
+ $text .= $1;
next component;
}
@pos = Text::Balanced::_match_variable(\$source,qr/\s*/);
=head1 VERSION
-This document describes version 2.10 of Switch,
-released Dec 29, 2003.
+This document describes version 2.14 of Switch,
+released Dec 29, 2008.
=head1 SYNOPSIS
- use Switch;
-
- switch ($val) {
+ use Switch;
- 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" }
- }
+ 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 (\&sub) { print "arg to subroutine" }
+ else { print "previous case not true" }
+ }
=head1 BACKGROUND
one could test for the existence of a single key in a series of hashes
(C<match if exists $c-E<gt>{$s}>).
-As L<perltodo> 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<switch> and C<case>. The C<switch> statement takes a
%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 $_ ~= /\W/
+ }
}
Note that C<switch>es can be nested within C<case> (or any other) blocks,
{
switch ($_[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' }
}
}
is usually a Bad Idea in a switch statement. However, this
is Perl, not a police state, so there I<is> a way to do it, if you must.
-If a C<case> block executes an untargetted C<next>, control is
+If a C<case> block executes an untargeted C<next>, control is
immediately transferred to the statement I<after> the C<case> statement
(i.e. usually another case), rather than out of the surrounding
C<switch> block.
If $val held the number C<1>, the above C<switch> block would call the
first three C<handle_...> subroutines, jumping to the next case test
-each time it encountered a C<next>. After the thrid C<case> block
+each time it encountered a C<next>. After the third C<case> block
was executed, control would jump to the end of the enclosing
C<switch> block.
case /\d/ { handle_dig_any(); }
}
-If an untargetted C<last> statement is executed in a case block, this
+If an untargeted C<last> statement is executed in a case block, this
immediately transfers control out of the enclosing C<switch> block
(in other words, there is an implicit C<last> at the end of each
normal C<case> block). Thus the previous example could also have been
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<case (sub { $_[0] < 10 })>, etc.; C<$_[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
use Switch '__';
- __ < 2 + __
+ __ < 2
is equivalent to:
- sub { $_[0] < 2 + $_[1] }
+ sub { $_[0] < 2 }
With C<__>, the previous ugly case statements can be rewritten:
This boolean expression is inevitably true, since both references are
non-false. Fortunately, the overloaded C<'bool'> operator catches this
-situation and flags it as a error.
+situation and flags it as an error.
=head1 DEPENDENCIES
=head1 AUTHOR
-Damian Conway (damian@conway.org)
+Damian Conway (damian@conway.org). This module is now maintained by Rafael
+Garcia-Suarez (rgarciasuarez@gmail.com) and more generally by the Perl 5
+Porters (perl5-porters@perl.org), as part of the Perl core.
=head1 BUGS
=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<//x> are indistinguishable from
+code chunks beginning with the division operator C</>. As a workaround
+you must use C<m/.../> or C<m?...?> for such patterns. Also, the presence
of regexes specified with raw C<?...?> delimiters may cause mysterious
errors. The workaround is to use C<m?...?> instead.
=head1 COPYRIGHT
- Copyright (c) 1997-2003, Damian Conway. All Rights Reserved.
+ Copyright (c) 1997-2008, 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.
https://perl5.git.perl.org / perl5.git / blobdiff