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 undef); ## 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> 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->(@_)' $code =~ s{ (?(\@_)}xg; ## '\&name' => '$name' $code =~ s<\\ \s* &($sub_name_re)\b> <\$LEXSUB_$1>xg; $subname \b ($bracket_re) >{}; } ## 'name' => '$name->()' $code =~ s{(?: ^ | (?()}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 Ced 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