Class::MethodMaker::V1Compat(3) 			User Contributed Perl Documentation			   Class::MethodMaker::V1Compat(3)

NAME

       Class::MethodMaker::V1Compat - V1 compatibility code for C::MM

SYNOPSIS

       This class is for internal implementation only.	It is not a public API.

DESCRIPTION

       Class::MethodMaker version 2 strives for backward-compatiblity with version 1 as far as possible.  That is to say, classes built with
       version 1 should work with few if any changes.  However, the calling conventions for building new classes are significantly different: this
       is necessary to achieve a greater consistency of arguments.

       Version 2 takes all arguments within a single arrayref:

	 use Class::MethodMaker
	   [ scalar => 'a' ];

       If arguments are presented as a list, then Class::MethodMaker assumes that this is a version 1 call, and acts accordingly.  Version 1
       arguments are passed and internally rephrased to version 2 arguments, and passed off to the version 2 engine.  Thus, the majority of
       version 1 calls can be upgraded to version 2 merely by rephrasing.  However, there are a number of behaviours that in version 1 that are
       internally inconsistent.  These behaviours are mimicked in version 1 mode as far as possible, but are not reproducible in version 2 (to
       allow version 2 clients to rely on a more internally consistent interface).

   Version 2 Implementations
       The nearest equivalent to each 1 component (slot) available in version 2 is shown below using the indicated data-structures & options to
       create a component called "a" that mimicks the V1 component behaviour as closely as possible:

       abstract
	     use Class::MethodMaker
	       [ abstract => 'a' ];

       boolean
	   Boolean is available as a backwards compatiblity hack, but there is currently no V2 equivalent.  It is likely that some replacement
	   mechanism will be introduced in the future, but that it will be incompatible with the version 1 boolean.

       code
	     use Class::MethodMaker
	       [ scalar => 'a' ];

	   Let's face it, the v1 store-if-it's-a-coderef-else-retrieve semantics are rather broken.  How do you pass a coderef as argument to one
	   of these?  It is on the TODO list to recognize code as fundamental restricted type (analogous to INTEGER), which would add in a
	   *_invoke method.

       copy
	     use Class::MethodMaker
	       [ copy => 'a' ];

	   The v2 method is the same as v1.

       counter
	     use Class::MethodMaker
	       [ scalar => [{-type => Class::MethodMaker::Constants::INTEGER}, 'a'] ];

       copy
       deep_copy
	     use Class::MethodMaker
	       [ copy => [ -deep => 'a' ] ];

       get_concat
	     use Class::MethodMaker
	       [ scalar => [{ -store_cb => sub {
					     defined $_[1] ? ( defined $_[3] ?
							       "$_[3] $_[1]" : $_[1] )
							   : undef;
					   }
			    },
			    'a' ]
	       ];

       get_set
	     use Class::MethodMaker
	       [ scalar => 'a' ];

       hash
	     use Class::MethodMaker
	       [ hash => 'a' ];

       key_attrib
	   Although v1 calls will continue to work, this is not supported in v2.

       key_with_create
	   Although v1 calls will continue to work, this is not supported in v2.

       list
	     use Class::MethodMaker
	       [ list => 'a' ];

	   Note that the "*" method now sets the whole array if given arguments.

       method
	   See "code".

       new
	     use Class::MethodMaker
	       [ new => 'a' ];

       new_hash_init
	     use Class::MethodMaker
	       [ new => [ -hash => 'a' ] ];

       new_hash_with_init
	     use Class::MethodMaker
	       [ new => [ -hash => -init => 'a' ] ];

       new_with_args
	   Although v1 calls will continue to work, this is not supported in v2, for it is a trivial application of "new_with_init".

       new_with_init
	     use Class::MethodMaker
	       [ new => [ -init => 'a' ] ];

       object
	     use Class::MethodMaker
	       [ scalar => [{ -type    => 'MyClass',
			      -forward => [qw/ method1 method2 /] }, 'a' ]
	       ];

       object_tie_hash
	     use Class::MethodMaker
	       [ hash => [{ -type      => 'MyClass',
			    -forward   => [qw/ method1 method2 /],
			    -tie_class => 'Tie::MyTie',
			    -tie_args  => [qw/ foo bar baz /],
			  }, 'a' ]
	       ];

       object_tie_list
	     use Class::MethodMaker
	       [ array => [{ -type	=> 'MyClass',
			     -forward	=> [qw/ method1 method2 /],
			     -tie_class => 'Tie::MyTie',
			     -tie_args	=> [qw/ foo bar baz /],
			   }, 'a' ]
	       ];

       set_once
	     use Class::MethodMaker
	       [ scalar => [{ -store_cb => sub {
					     die "Already stored $_[3]"
					       if @_ > 3;
					   }
			    },
			    'a' ]
	       ];

       set_once_static
	     use Class::MethodMaker
	       [ scalar => [{ -store_cb => sub {
					     die "Already stored $_[3]"
					       if @_ > 3;
					   },
			      -static	=> 1,
			    },
			    'a' ]
	       ];

       singleton
	     use Class::MethodMaker
	       [ new => [ -singleton => -hash => -init => 'a' ] ];

       static_get_set
	     use Class::MethodMaker
	       [ scalar => [ -static => 'a' ], ];

       static_hash
	     use Class::MethodMaker
	       [ hash => [ -static => 'a' ], ];

       static_list
	     use Class::MethodMaker
	       [ list => [ -static => 'a' ], ];

       tie_hash
	     use Class::MethodMaker
	       [ hash => [ { -tie_class => 'MyTie',
			     -tie_args	=> [qw/ foo bar baz /],
			   } => 'a' ], ];

       tie_list
	     use Class::MethodMaker
	       [ array => [ { -tie_class => 'MyTie',
			      -tie_args  => [qw/ foo bar baz /],
			    } => 'a' ], ];

       tie_scalar
	     use Class::MethodMaker
	       [ scalar => [ { -tie_class => 'MyTie',
			       -tie_args  => [qw/ foo bar baz /],
			     } => 'a' ], ];

   Caveats & Expected Breakages
       The following version 1 component (slot) types are not currently supported in version 2:

       grouped_fields
       hash_of_lists
       listed_attrib
       struct

EXAMPLES

BUGS

REPORTING BUGS

       Email the development mailing list "class-mmaker-devel@lists.sourceforge.net".

AUTHOR

       Martyn J. Pearce

COPYRIGHT

       Copyright (c) 2003, 2004 Martyn J. Pearce.  This program is free software; you can redistribute it and/or modify it under the same terms as
       Perl itself.

SEE ALSO

perl v5.12.1							    2008-12-03					   Class::MethodMaker::V1Compat(3)