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=head1 TITLE
Objects : Rationalizing C<ref>, C<attribute::reftype>, and C<builtin::blessed>
=head1 VERSION
Maintainer: Damian Conway <[EMAIL PROTECTED]>
Date: 14 September 2000
Mailing List: [EMAIL PROTECTED]
Number: 224
Version: 1
Status: Developing
=head1 ABSTRACT
This RFC proposes that rather than three separate mechanisms (in three
separate namespaces) to determine object typing information, Perl 6
simply extend the C<ref> function to return all the necessary
information in a list context.
=head1 DESCRIPTION
In Perl 5, the class into which an object is blessed is returned by
calling C<ref> on a reference to that object. To determine the
underlying implementation type of the object, C<attribute::reftype> is
used. To determine whether or not a reference refers to a blessed
object, <builtin::blessed> is used.
It is proposed that the behaviour of C<ref> be altered in Perl 6 so that
in a list context it returns up to two values: the underlying
implementation type of the object (always returned), and the class into
which the object is blessed (only if the object I<is> blessed).
Thus:
if (builtin::blessed $ref) {
$type = attribute::reftype $ref;
$class = ref $ref;
}
else {
$type = ref $ref;
$class = "<no class>";
}
print "Object of type $type, blessed into $class\n";
Would become:
($type, $class) = ref($ref);
$class ||= "<no class>";
print "Object of type $type, blessed into $class\n";
=head1 MIGRATION ISSUES
All existing calls to C<ref> in a list context would have to be
translated to C<scalar ref>.
=head1 IMPLEMENTATION
Trivial.
=head1 REFERENCES
None.
