File Coverage

blib/lib/Attribute/Generator.pm

Criterion	Covered	Total	%
statement	10	12	83.3
branch			n/a
condition			n/a
subroutine	4	4	100.0
pod			n/a
total	14	16	87.5

package Attribute::Generator;

use strict;
use warnings;
our $VERSION = '0.02';

use Attribute::Handlers;
use Coro::State 4.91;

use base qw(Exporter);

our @EXPORT = qw(yield);

sub UNIVERSAL::Generator : ATTR(CODE) {
    my($package, $symbol, $refent) = @_;
    no warnings 'redefine';
    *{$symbol} = sub { new Attribute::Generator::State $refent, @_ };
}

our @stack = (Coro::State->new()); # Generator stack;

sub yield {
    $stack[-1]{_sent} = \@_;
    pop(@stack)->transfer($stack[-1]);
    my $sent = delete $stack[-1]{_sent} or return; # from send()
    wantarray ? @$sent : $sent->[0];
}

{
    package Attribute::Generator::State;
    use base qw(Coro::State);

    use overload (
        '@{}' => '__list__',
        '<>'  => 'next',
    );

    sub _run_generator {
        eval {
            &{+shift}; #execute the code
        };

        $stack[-2]->throw($@) if $@;
        while() {
            pop(@stack)->transfer($stack[-1]);
            delete $stack[-1]{_sent}; # clear send()ed.
        }
    }

    sub new {
        shift->SUPER::new(\&_run_generator, @_)
    }

    sub next {
        my($self) = @_;
        push @stack, $self;
        $stack[-2]->transfer($self); # resume
        my $ret = delete $self->{_sent} or return;
        wantarray ? @$ret : $ret->[0];
    }

    sub send {
        shift->{_sent} = \@_;
    }

    sub __list__ {
        my($self) = @_;
        my @ret;
        while(my @tmp = $self->next) {
            push @ret, @tmp;
        }
        \@ret;
    }
}

1;
__END__