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package Forest::Tree::Constructor;
use Moose::Role;
our $VERSION = '0.09';
our $AUTHORITY = 'cpan:STEVAN';
requires "tree_class";
sub create_new_subtree {
my ($self, %options) = @_;
my $node = $options{node};
if (blessed($node) && $node->isa('Forest::Tree::Pure')) {
# when node is an tree object we assume that it's a prototype of a tree
# node to be filled in
# remove meaningless keys
delete $options{node};
delete $options{children} if exists $options{children} and not @{ $options{children} };
# nothing left to be done if the option cleanup deleted all keys
return $node unless keys %options;
if ( $node->child_count == 0 ) {
if ( $node->isa("Forest::Tree") ) {
# mutable trees get modified
foreach my $key ( keys %options ) {
$node->$key( $options{$key} );
}
return $node;
}
else {
# pure trees get cloned
return $node->clone(%options);
}
}
else {
# i suppose $options{children} could be appended to $node->children
# if there are any, but that doesn't really make sense IMHO, might
# as well write your own builder at that point instead of kludging
# it with the parser callback for the simple text loader or something
confess("Can't override children from proto node");
}
}
else {
return $self->tree_class->new(%options);
}
}
# ex: set sw=4 et
no Moose::Role; 1;
__END__
=head1 NAME
Forest::Tree::Constructor - An abstract role for tree factories
=head1 SYNOPSIS
with qw(Forest::Tree::Constructor);
sub tree_class { ... }
sub foo {
$self->create_new_subtree( ... )
}
=head1 DESCRIPTION
This role provides the C<create_new_subtree> method as required by
L<Forest::Tree::Builder> and L<Forest::Tree::Loader>/L<Forest::Tree::Reader>.
See L<Forest::Tree::Builder> for the reccomended usage.
=head1 BUGS
All complex software has bugs lurking in it, and this module is no
exception. If you find a bug please either email me, or add the bug
to cpan-RT.
=head1 AUTHOR
Yuval Kogman
=head1 COPYRIGHT AND LICENSE
Copyright 2008-2010 Infinity Interactive, Inc.
L<http://www.iinteractive.com>
This library is free software; you can redistribute it and/or modify
it under the same terms as Perl itself.
=cut
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