README for Class::BlackHole Time-stamp: "2000-05-13 19:35:25 MDT" NAME Class::BlackHole - base class to treat unhandled method calls as no-ops SYNOPSIS use Class::BlackHole; # set up a class X, to inherit from Class::BlackHole @X::ISA = qw(Class::BlackHole); # put a method in it sub X::zaz { 123123; } print "Zaz is <", X->zaz, ">\n"; print "Flork is <", X->flork, ">\n"; print "can zaz : <", X->can('zaz'), ">\n"; print "can flork : <", X->can('flork'), ">\n"; The above code prints: Zaz is <123123> Flork is <> can zaz : can flork : <> DESCRIPTION Normally, if you try to call a method that there's no handler for, you get an error: Can't locate object method "flork" via package "X". But for classes that inherit from Class::BlackHole, unhandled methods become just no-operations. CAVEATS Be sure to have Class::BlackHole be the absolute last item in your class's ISA list. This class will almost definitely not work right as part of any ISA tree that has multiple inheritance. IMPLEMENTATION Class::BlackHole just traps everything with an AUTOLOAD sub that is a no-operation. HOWEVER, what makes Class::Blackhole different than merely: @Class::BlackHole::ISA = (); sub Class::BlackHole::AUTOLOAD { } is that this would (unhappily) trap calls to the helpful methods in UNIVERSAL, like can, VERSION, and isa. Class::BlackHole aliases those methods (or better said, all subs in package UNIVERSAL) into its own package, so that they'll be accessible instead of being caught by the AUTOLOAD. FUNCTIONS AND METHODS This module provides no functions or methods. It exports no symbols into the calling package or anywhere else. DISCLAIMER This program is distributed in the hope that it will be useful, but without any warranty; without even the implied warranty of merchantability or fitness for a particular purpose. But let me know if it gives you any problems, OK? COPYRIGHT Copyright 1999, 2000, Sean M. Burke sburke@cpan.org, all rights reserved. This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself. AUTHOR Sean M. Burke sburke@cpan.org PREREQUISITES This suite requires Perl 5; I've only used it under Perl 5.004, so for anything lower, you're on your own. Class::BlackHole doesn't use any nonstandard modules. INSTALLATION You install Class::BlackHole, as you would install any perl module library, by running these commands: perl Makefile.PL make make test make install If you want to install a private copy of Class::BlackHole in your home directory, then you should try to produce the initial Makefile with something like this command: perl Makefile.PL LIB=~/perl DOCUMENTATION POD-format documentation is included in BlackHole.pm. POD is readable with the 'perldoc' utility. See ChangeLog for recent changes. MACPERL INSTALLATION NOTES Don't bother with the makefiles. Just make a Class directory in your MacPerl site_lib or lib directory, and move BlackHole.pm into there. SUPPORT Questions, bug reports, useful code bits, and suggestions for Class::BlackHole should just be sent to me at sburke@cpan.org AVAILABILITY The latest version of Class::BlackHole is available from the Comprehensive Perl Archive Network (CPAN). Visit to find a CPAN site near you.