package Class::Inner;

use vars qw/$VERSION/;

$VERSION = 0.200_001;

use strict;
use Carp;

=head1 NAME

Class::Inner - A perlish implementation of Java like inner classes


    use Class::Inner;

    my $object = Class::Inner->new(
	parent => 'ParentClass',
        methods => { method => sub { ... } }, },
        constructor => 'new',
        args => [@constructor_args],


Yet another implementation of an anonymous class with per object
overrideable methods, but with the added attraction of sort of working
dispatch to the parent class's method.

=head2 METHODS

=over 4

=item B<new HASH>

Takes a hash like argument list with the following keys.

=over 4

=item B<parent>

The name of the parent class. Note that you can only get single
inheritance with this or B<SUPER> won't work.

=item B<methods>

A hash, keys are method names, values are CODEREFs.

=item B<constructor>

The name of the constructor method. Defaults to 'new'.

=item B<args>

An anonymous array of arguments to pass to the constructor. Defaults
to an empty list.


Returns an object in an 'anonymous' class which inherits from the
parent class. This anonymous class has a couple of 'extra' methods:

=over 4

=item B<SUPER>

If you were to pass something like

    $obj = Class::Inner->new(
	parent  => 'Parent',
	methods => { method =>  sub { ...; $self->SUPER::method(@_) } },

then C<$self-C<gt>SUPER::method> almost certainly wouldn't do what you expect,
so we provide the C<SUPER> method which dispatches to the parent 
implementation of the current method. There seems to be no good way of
getting the full C<SUPER::> functionality, but I'm working on it.

=item B<DESTROY>

Because B<Class::Inner> works by creating a whole new class name for your
object, it could potentially leak memory if you create a lot of them. So we
add a C<DESTROY> method that removes the class from the symbol table once
it's finished with.

If you need to override a parent's DESTROY method, adding a call to
C<Class::Inner::clean_symbol_table(ref $self)> to it. Do it at the
end of the method or your other method calls won't work.




sub new {
    my $class	    = shift;
    my %args	    = ref($_[0]) ? %{$_[0]} : @_;
    my $parent	    = $args{parent} or
	croak "Can't work without a parent class\n";
    my %methods	    = %{$args{methods}||{}};
    my $constructor = $args{constructor} || 'new';
    my @constructor_args = @{$args{args} || []};

    my $anon_class = $class->new_classname;

    no strict 'refs';

    @{"$anon_class\::ISA"} = $parent;

    foreach my $methodname (keys %methods) {
	*{"$anon_class\::$methodname"} = sub {
	    local $Class::Inner::target_method = $methodname;

    # Add the SUPER method.

    unless (exists $methods{SUPER}) {
	*{"$anon_class\::SUPER"} = sub {
	    my $self = shift;
	    my $target_method =
		join '::', $parent, $Class::Inner::target_method;

    unless (exists $methods{DESTROY}) {
	*{"$anon_class\::DESTROY"} = sub {
	    my $self = shift;
	    bless $self, $parent;
    # Instantiate
    my $obj = $anon_class->new(@constructor_args);

=item B<clean_symbol_table>

The helper subroutine that DESTROY uses to remove the class from the
symbol table.


sub clean_symbol_table {
    my $class = shift;
    no strict 'refs';
    undef %{"${class}::"};	

=item B<new_classname>

Returns a name for the next anonymous class.


    my $class_counter;

    sub new_classname {
	my $baseclass = shift;
	return "$baseclass\::__A" . $class_counter++;



=head1 AUTHOR

Maintained by Arun Prasaad  C<< <> >>

Copyright (c) 2001 by Piers Cawley E<lt>pdcawley@iterative-software.comE<gt>.

All rights reserved. This program is free software; you can redistribute it
and/or modify it under the same terms as perl itself.

Thanks to the Iterative Software people: Leon Brocard, Natalie Ford and 
Dave Cross. Also, this module was written initially for use in the
PerlUnit project, AKA Test::Unit. Kudos to Christian Lemburg and the rest
of that team.

=head1 SEE ALSO

There are a million and one differen Class constructors available on CPAN,
none of them does quite what I want, so I wrote this one to add to
that population where hopefully it will live and thrive.

=head1 BUGS

Bound to be some. Actually the C<SUPER> method is a workaround for what
I consider to be a bug in perl.