This and other RFCs are available on the web at http://dev.perl.org/rfc/ =head1 TITLE PRAYER - what gets said when you C<bless> something =head1 VERSION Maintainer: Simon Cozens <[EMAIL PROTECTED]> Date: 25 Sep 2000 Last Modified: 25 Sep 2000 Mailing List: [EMAIL PROTECTED] Number: 307 Version: 2 Status: Withdrawn =head1 NOTES ON WITHDRAWL Damian Conway noted: RFC 189 covers this. =head1 ABSTRACT This RFC proposes a special sub, C<PRAYER>, which is automatically called on C<bless>ing. =head1 DESCRIPTION The abstract more or less says it all, but this is more than just a joke. Suppose, for instance, your class needs to do some initialisation whenever a new object is created; C<PRAYER> would be where the class initialisation takes place. There's also the more interesting and (IMHO) important issue of reblessing; that is, changing the class of an object. There are times when you want to do this, but it's hairy because you have to know the workings of both classes. However, if you have C<PRAYER> called automatically on C<bless>ing, you can automagically "cast" objects between classes. For instance, an object in class X would get changed to an object in class Y with bless $obj, "Y"; Perl would then perform the reblessing and call: package Y; sub PRAYER ($object, $oldclass) { if ($oldclass eq "X") { ... } else { die "Can't cast an $oldclass to a Y"; } } You may also use this method as a form of "pre-constructor", or even, on simple enough classes, a constructor proper. Maybe subs to cast between classes should somehow be shared between the two classes; the special sub C<INTERCESSION> would be the obvious place for that. =head1 IMPLEMENTATION Adding a method call to the end of C<bless> should not be tricky. =head1 REFERENCES None.
