package Forks::Super::Tie::Enum;
use Carp;
use strict;
use warnings;
use vars qw(%ATTR %VALUE);

# A tie'd scalar value that can only take on values
# from a pre-specified list.
# Used in Forks::Super for $ON_BUSY and $QUEUE_INTERRUPT

sub TIESCALAR {
    my ($class, @attr) = @_;
    my $self;
    bless \$self, $class;
    $VALUE{\$self} = $attr[0];
    $ATTR{\$self} = [ @attr ];
    return \$self;
}

sub FETCH {
    my $self = shift;
    return $VALUE{$self};
}

sub STORE {
    my ($self,$value) = @_;
    foreach my $attr (@{$ATTR{$self}}) {
	if (uc $value eq uc $attr) {
	    $VALUE{$self} = $attr;
	    return;
	}
    }
    if ($ATTR{''}) {
	$VALUE{$self} = '';
    } else {
	carp "Invalid assignment to enumerated tied scalar";
    }
    return;
}

sub _has_attr {
    my ($obj, $value) = @_;
    foreach my $attr (@{$ATTR{$obj}}) {
	if (uc $value eq uc $attr) {
	    return 1;
	}
    }
    return 0;
}

sub _get_value {
    my ($obj) = @_;
    return $VALUE{$obj};
}

1;