Category: | Miscellaneous |
Author/Contact Info | /msg broquaint |
Description: | Now available on CPAN - Sub::Lexical
See the POD for info about the module. Basically I'm just throwing this out to see if anyone can find any use for this since it's really just syntactic sugar. There's still a couple of bugs but they should go if I ever bother putting it somewhere important like CPAN or the Code Section on Perl Monks. Hey wait a second ... And if anyone actually wants to play about with it a bit further I can provide them with an actual package (tests and all!) Any improvements/suggestions/condemnations welcome |
package Sub::Lexical; $VERSION = 0.7; use strict; use Regexp::Common; use Carp qw(croak cluck); use constant DEBUG => 0; sub new { my $class = shift; croak('Sub::Lexical constructor must be called as a class method') if $class ne 'Sub::Lexical'; cluck("arguments passed to new() aren't in pair form") if @_ % 2 != 0; ## don't stuff list in if it don't fit my $self = { @_ % 2 == 0 ? @_ : () }; bless($self, $class); } my $brackets_re = $RE{balanced}{-parens => '{}'}; my $paren_re = $RE{balanced}{-parens => '()'}; my $sub_name_re = qr{[_a-zA-Z](?:[\w_]+)?}; my $sub_proto_re = qr{\([\$%\\@&\s]*\)}; my $sub_attrib_re = qr{(?:\s*:\s*$sub_name_re\s*(?:$paren_re)?)*}o; # my sub foobar (proto) : attrib { "code" } my $sub_match_re = qr/ my \s+ sub \s+ ($sub_name_re) \s* ( ${sub_proto_re} ? ${sub_attrib_re} ? ) ? \s* ( $brackets_re ) ? \s* ; ? /xo; ## core functions which may expect a function e.g goto &foo my $core_funcs = join '|', qw(do defined eval goto grep map sort un +def); ## things that *can't* come before a bareword my $ops_before = qr/(?<! \$ | % | @ | ' | " ) | (?>! q. | -> ) | (?>! q[ ]\w | qq. ) | (?>! qq[ ]\w )/x; sub lexfilter { my $self = shift; croak('filter_code() must be called as an object method') unless $self->isa('Sub::Lexical'); my $code = shift; study $code; while(my($subname, $subextra, $subcode) = $code =~ /$sub_match_re/ +) { push @{$self->{info}}, { name => $subname, extra => $subextra, code => $subcode }; my $lexname = "\$LEXSUB_${subname}"; ## 'my sub name {}' => 'my $name; $name = sub {};' $code =~ s<$sub_match_re> <my \$LEXSUB_$1; \$LEXSUB_$1 = sub $2 $3;>g; ## '&name()' => '$name->()' $code =~ s< &? # optional & $subname # 'subname' \s* # 0+ whitespace ( # group $1 $paren_re # balanced parens ) # optional group $1 >{"$lexname->" . ($1 || '()')}exg; ## 'goto &name' => 'goto &$name' $code =~ s<($core_funcs) \s* &$subname\b> <$1 &$lexname>xg; ## '&name' => '$name->(@_)' $code =~ s{ (?<!\\) &$subname\b} {$lexname->(\@_)}xg; ## '\&name' => '$name' $code =~ s<\\ \s* &($sub_name_re)\b> <\$LEXSUB_$1>xg; $subname \b ($bracket_re) >{}; } ## 'name' => '$name->()' $code =~ s{(?: ^ | (?<! LEXSUB_) ( (?: $ops_before | \s+) \s* +) ) $subname \b } {$1$lexname->()}xmg; } return $code; } use Filter::Simple; FILTER_ONLY code => sub { my $f = Sub::Lexical->new(); $_ = $f->filter_code($_); }; q(package activated); __END__ =pod =head1 NAME Sub::Lexical - implement lexically scoped subroutines =head1 SYNOPSIS use Sub::Lexical; sub foo { my @vals = @_; my sub bar { my $arg = shift; print "\$arg is $arg\n"; print "\$vals are @vals\n"; } bar("just a string"); my sub quux (@) { print "quux got args [@_]\n"; } takesub(\&quux, qw(ichi ni san shi)); } sub takesub { print "executing given sub\n\t"; shift->(@_[1..$#_]) } foo(qw(a bunch of args)); =head1 DESCRIPTION Using this module will give your code the illusion of having lexically scoped subroutines. This is because where ever a sub is lexically declared it will really just turn into a C<my()>ed scalar pointing to a coderef. However the lexically scoped subs seem to work as one might expect them to. They can see other lexically scoped variables and subs, and will fall out of scope like they should. You can pass them around like coderefs, give them attributes and prototypes too if you're feeling particularly brave =head1 SEE ALSO perlsub, Regex::Common, Filter::Simple =head1 THANKS Damian Conway and PerlMonks for giving me the skills and resources to write this =head1 AUTHOR by Dan Brook =head1 COPYRIGHT Copyright (c) 2002, Dan Brook. All Rights Reserved. This module is free software. It may be used, redistributed and/or modified under the same terms as Perl itself. =cut |
Back to
Code Catacombs