use vars qw($VERSION);
use Carp;
-$VERSION = '2.03';
+$VERSION = '2.10_01';
# LOAD FILTERING MODULE...
# CATCH ATTEMPTS TO CALL case OUTSIDE THE SCOPE OF ANY switch
-$::_S_W_I_T_C_H = sub { croak "case statement not in switch block" };
+$::_S_W_I_T_C_H = sub { croak "case/when statement not in switch/given block" };
my $offset;
my $fallthrough;
+my ($Perl5, $Perl6) = (0,0);
sub import
{
- $DB::single = 1;
$fallthrough = grep /\bfallthrough\b/, @_;
$offset = (caller)[2]+1;
filter_add({}) unless @_>1 && $_[1] eq 'noimport';
*{"${pkg}::$_"} = \&$_;
}
*{"${pkg}::__"} = \&__ if grep /__/, @_;
+ $Perl6 = 1 if grep(/Perl\s*6/i, @_);
+ $Perl5 = 1 if grep(/Perl\s*5/i, @_) || !grep(/Perl\s*6/i, @_);
1;
}
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;
- # print STDERR $_;
return $status;
}
sub line
{
my ($pretext,$offset) = @_;
- ($pretext=~tr/\n/\n/)+$offset,
+ ($pretext=~tr/\n/\n/)+($offset||0);
}
sub is_block
return !$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 $casecounter = 1;
sub filter_blocks
{
my ($source, $line) = @_;
- return $source unless $source =~ /case|switch/;
+ return $source unless $Perl5 && $source =~ /case|switch/
+ || $Perl6 && $source =~ /when|given|default/;
pos $source = 0;
my $text = "";
component: while (pos $source < length $source)
$text .= q{use Switch 'noimport'};
next component;
}
- my @pos = Text::Balanced::_match_quotelike(\$source,qr/\s*/,1,1);
+ my @pos = Text::Balanced::_match_quotelike(\$source,qr/\s*/,1,0);
if (defined $pos[0])
{
- $text .= " " . substr($source,$pos[2],$pos[18]-$pos[2]);
+ my $pre = substr($source,$pos[0],$pos[1]); # matched prefix
+ $text .= $pre . substr($source,$pos[2],$pos[18]-$pos[2]);
+ next component;
+ }
+ if ($source =~ m/\G\s*($pod_or_DATA)/gc) {
next component;
}
@pos = Text::Balanced::_match_variable(\$source,qr/\s*/);
if (defined $pos[0])
{
- $text .= " " . substr($source,$pos[0],$pos[4]-$pos[0]);
+ $text .= " " if $pos[0] < $pos[2];
+ $text .= substr($source,$pos[0],$pos[4]-$pos[0]);
next component;
}
- if ($source =~ m/\G(\n*)(\s*)switch\b(?=\s*[(])/gc)
+ if ($Perl5 && $source =~ m/\G(\n*)(\s*)(switch)\b(?=\s*[(])/gc
+ || $Perl6 && $source =~ m/\G(\n*)(\s*)(given)\b(?=\s*[(])/gc
+ || $Perl6 && $source =~ m/\G(\n*)(\s*)(given)\b(.*)(?=\{)/gc)
{
+ my $keyword = $3;
+ my $arg = $4;
$text .= $1.$2.'S_W_I_T_C_H: while (1) ';
- @pos = Text::Balanced::_match_codeblock(\$source,qr/\s*/,qr/\(/,qr/\)/,qr/[[{(<]/,qr/[]})>]/,undef)
- or do {
- die "Bad switch statement (problem in the parentheses?) near $Switch::file line ", line(substr($source,0,pos $source),$line), "\n";
- };
- my $arg = filter_blocks(substr($source,$pos[0],$pos[4]-$pos[0]),line(substr($source,0,$pos[0]),$line));
+ unless ($arg) {
+ @pos = Text::Balanced::_match_codeblock(\$source,qr/\s*/,qr/\(/,qr/\)/,qr/[[{(<]/,qr/[]})>]/,undef)
+ or do {
+ die "Bad $keyword statement (problem in the parentheses?) near $Switch::file line ", line(substr($source,0,pos $source),$line), "\n";
+ };
+ $arg = filter_blocks(substr($source,$pos[0],$pos[4]-$pos[0]),line(substr($source,0,$pos[0]),$line));
+ }
$arg =~ s {^\s*[(]\s*%} { ( \\\%} ||
$arg =~ s {^\s*[(]\s*m\b} { ( qr} ||
$arg =~ s {^\s*[(]\s*/} { ( qr/} ||
$arg =~ s {^\s*[(]\s*qw} { ( \\qw};
@pos = Text::Balanced::_match_codeblock(\$source,qr/\s*/,qr/\{/,qr/\}/,qr/\{/,qr/\}/,undef)
or do {
- die "Bad switch statement (problem in the code block?) near $Switch::file line ", line(substr($source,0, pos $source), $line), "\n";
+ die "Bad $keyword statement (problem in the code block?) near $Switch::file line ", line(substr($source,0, pos $source), $line), "\n";
};
my $code = filter_blocks(substr($source,$pos[0],$pos[4]-$pos[0]),line(substr($source,0,$pos[0]),$line));
$code =~ s/{/{ local \$::_S_W_I_T_C_H; Switch::switch $arg;/;
$text .= $code . 'continue {last}';
next component;
}
- elsif ($source =~ m/\G(\s*)(case\b)(?!\s*=>)/gc)
+ elsif ($Perl5 && $source =~ m/\G(\s*)(case\b)(?!\s*=>)/gc
+ || $Perl6 && $source =~ m/\G(\s*)(when\b)(?!\s*=>)/gc
+ || $Perl6 && $source =~ m/\G(\s*)(default\b)(?=\s*\{)/gc)
{
- $text .= $1."if (Switch::case";
- if (@pos = Text::Balanced::_match_codeblock(\$source,qr/\s*/,qr/\{/,qr/\}/,qr/\{/,qr/\}/,undef)) {
+ my $keyword = $2;
+ $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 .= " sub" if is_block $code;
- $text .= " " . filter_blocks($code,line(substr($source,0,$pos[0]),$line)) . ")";
+ $text .= " " if $pos[0] < $pos[2];
+ $text .= "sub " if is_block $code;
+ $text .= filter_blocks($code,line(substr($source,0,$pos[0]),$line)) . ")";
}
elsif (@pos = Text::Balanced::_match_codeblock(\$source,qr/\s*/,qr/[[(]/,qr/[])]/,qr/[[({]/,qr/[])}]/,undef)) {
my $code = filter_blocks(substr($source,$pos[0],$pos[4]-$pos[0]),line(substr($source,0,$pos[0]),$line));
$code =~ s {^\s*[(]\s*m\b} { ( qr} ||
$code =~ s {^\s*[(]\s*/} { ( qr/} ||
$code =~ s {^\s*[(]\s*qw} { ( \\qw};
- $text .= " $code)";
+ $text .= " " if $pos[0] < $pos[2];
+ $text .= "$code)";
+ }
+ elsif ($Perl6 && do{@pos = Text::Balanced::_match_variable(\$source,qr/\s*/)}) {
+ my $code = filter_blocks(substr($source,$pos[0],$pos[4]-$pos[0]),line(substr($source,0,$pos[0]),$line));
+ $code =~ s {^\s*%} { \%} ||
+ $code =~ s {^\s*@} { \@};
+ $text .= " " if $pos[0] < $pos[2];
+ $text .= "$code)";
}
- elsif ( @pos = Text::Balanced::_match_quotelike(\$source,qr/\s*/,1,1)) {
+ elsif ( @pos = Text::Balanced::_match_quotelike(\$source,qr/\s*/,1,0)) {
my $code = substr($source,$pos[2],$pos[18]-$pos[2]);
$code = filter_blocks($code,line(substr($source,0,$pos[2]),$line));
$code =~ s {^\s*m} { qr} ||
$code =~ s {^\s*/} { qr/} ||
$code =~ s {^\s*qw} { \\qw};
- $text .= " $code)";
+ $text .= " " if $pos[0] < $pos[2];
+ $text .= "$code)";
}
- elsif ($source =~ m/\G\s*(([^\$\@{])[^\$\@{]*)(?=\s*{)/gc) {
+ elsif ($Perl5 && $source =~ m/\G\s*(([^\$\@{])[^\$\@{]*)(?=\s*{)/gc
+ || $Perl6 && $source =~ m/\G\s*([^;{]*)()/gc) {
my $code = filter_blocks($1,line(substr($source,0,pos $source),$line));
$text .= ' \\' if $2 eq '%';
$text .= " $code)";
}
else {
- die "Bad case statement (invalid case value?) near $Switch::file line ", line(substr($source,0,pos $source), $line), "\n";
+ die "Bad $keyword statement (invalid $keyword value?) near $Switch::file line ", line(substr($source,0,pos $source), $line), "\n";
}
- @pos = Text::Balanced::_match_codeblock(\$source,qr/\s*/,qr/\{/,qr/\}/,qr/\{/,qr/\}/,undef)
+ die "Missing opening brace or semi-colon after 'when' value near $Switch::file line ", line(substr($source,0,pos $source), $line), "\n"
+ unless !$Perl6 || $source =~ m/\G(\s*)(?=;|\{)/gc;
+
+ do{@pos = Text::Balanced::_match_codeblock(\$source,qr/\s*/,qr/\{/,qr/\}/,qr/\{/,qr/\}/,undef)}
or do {
if ($source =~ m/\G\s*(?=([};]|\Z))/gc) {
$casecounter++;
next component;
}
- die "Bad case statement (problem in the code block?) near $Switch::file line ", line(substr($source,0,pos $source),$line), "\n";
+ die "Bad $keyword statement (problem in the code block?) near $Switch::file line ", line(substr($source,0,pos $source),$line), "\n";
};
my $code = filter_blocks(substr($source,$pos[0],$pos[4]-$pos[0]),line(substr($source,0,$pos[0]),$line));
$code =~ s/}(?=\s*\Z)/;last S_W_I_T_C_H }/
next component;
}
- $source =~ m/\G(\s*(\w+|#.*\n|\W))/gc;
+ $source =~ m/\G(\s*(-[sm]\s+|\w+|#.*\n|\W))/gc;
$text .= $1;
}
$text;
return 1;
}
-sub case($) { $::_S_W_I_T_C_H->(@_); }
+sub case($) { local $SIG{__WARN__} = \&carp;
+ $::_S_W_I_T_C_H->(@_); }
# IMPLEMENT __
=head1 VERSION
-This document describes version 2.03 of Switch,
-released May 15, 2001.
+This document describes version 2.10 of Switch,
+released Dec 29, 2003.
=head1 SYNOPSIS
while (<>) {
switch ($_) {
- case %special { print "homer\n"; } # if $special{$_}
- case /a-z/i { print "alpha\n"; } # if $_ =~ /a-z/i
- case [1..9] { print "small num\n"; } # if $_ in [1..9]
+ case (%special) { print "homer\n"; } # if $special{$_}
+ 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 $age = <>;
is usually a Bad Idea in a switch statement. However, this
is Perl, not a police state, so there I<is> a way to do it, if you must.
-If a C<case> block executes an untargetted C<next>, control is
+If a C<case> block executes an untargeted C<next>, control is
immediately transferred to the statement I<after> the C<case> statement
(i.e. usually another case), rather than out of the surrounding
C<switch> block.
case /\d/ { handle_dig_any(); }
}
-If an untargetted C<last> statement is executed in a case block, this
+If an untargeted C<last> statement is executed in a case block, this
immediately transfers control out of the enclosing C<switch> block
(in other words, there is an implicit C<last> at the end of each
normal C<case> block). Thus the previous example could also have been
+=head2 Alternative syntax
+
+Perl 6 will provide a built-in switch statement with essentially the
+same semantics as those offered by Switch.pm, but with a different
+pair of keywords. In Perl 6 C<switch> will be spelled C<given>, and
+C<case> will be pronounced C<when>. In addition, the C<when> statement
+will not require switch or case values to be parenthesized.
+
+This future syntax is also (largely) available via the Switch.pm module, by
+importing it with the argument C<"Perl6">. For example:
+
+ use Switch 'Perl6';
+
+ given ($val) {
+ when 1 { handle_num_1(); }
+ when ($str1) { handle_str_1(); }
+ 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
+ambiguous in Perl 5.
+
+Note too that you can mix and match both syntaxes by importing the module
+with:
+
+ use Switch 'Perl5', 'Perl6';
+
+
=head2 Higher-order Operations
One situation in which C<switch> and C<case> do not provide a good
=head1 AUTHOR
-Damian Conway (damian@conway.org)
+Damian Conway (damian@conway.org). The maintainer of this module is now Rafael
+Garcia-Suarez (rgarciasuarez@free.fr).
=head1 BUGS
There are undoubtedly serious bugs lurking somewhere in code this funky :-)
Bug reports and other feedback are most welcome.
+=head1 LIMITATIONS
+
+Due to the heuristic nature of Switch.pm's source parsing, the presence
+of regexes specified with raw C<?...?> delimiters may cause mysterious
+errors. The workaround is to use C<m?...?> instead.
+
+Due to the way source filters work in Perl, you can't use Switch inside
+an string C<eval>.
+
+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) 1997-2000, Damian Conway. All Rights Reserved.
-This module is free software; you can redistribute it and/or
-modify it under the same terms as Perl itself.
+ Copyright (c) 1997-2003, 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.
projects / p5sagit/p5-mst-13.2.git / blobdiff