1Class::MethodMaker::V1CUosmepratC(o3n)tributed Perl DocuCmleanstsa:t:iMoenthodMaker::V1Compat(3)
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NAME

6       Class::MethodMaker::V1Compat - V1 compatibility code for C::MM
7

SYNOPSIS

9       This class is for internal implementation only.  It is not a public
10       API.
11

DESCRIPTION

13       Class::MethodMaker version 2 strives for backward-compatibility with
14       version 1 as far as possible.  That is to say, classes built with
15       version 1 should work with few if any changes.  However, the calling
16       conventions for building new classes are significantly different: this
17       is necessary to achieve a greater consistency of arguments.
18
19       Version 2 takes all arguments within a single arrayref:
20
21         use Class::MethodMaker
22           [ scalar => 'a' ];
23
24       If arguments are presented as a list, then Class::MethodMaker assumes
25       that this is a version 1 call, and acts accordingly.  Version 1
26       arguments are passed and internally rephrased to version 2 arguments,
27       and passed off to the version 2 engine.  Thus, the majority of version
28       1 calls can be upgraded to version 2 merely by rephrasing.  However,
29       there are a number of behaviours that in version 1 that are internally
30       inconsistent.  These behaviours are mimicked in version 1 mode as far
31       as possible, but are not reproducible in version 2 (to allow version 2
32       clients to rely on a more internally consistent interface).
33
34   Version 2 Implementations
35       The nearest equivalent to each 1 component (slot) available in version
36       2 is shown below using the indicated data-structures & options to
37       create a component called "a" that mimics the V1 component behaviour as
38       closely as possible:
39
40       abstract
41             use Class::MethodMaker
42               [ abstract => 'a' ];
43
44       boolean
45           Boolean is available as a backwards compatibility hack, but there
46           is currently no V2 equivalent.  It is likely that some replacement
47           mechanism will be introduced in the future, but that it will be
48           incompatible with the version 1 boolean.
49
50       code
51             use Class::MethodMaker
52               [ scalar => 'a' ];
53
54           Let's face it, the v1 store-if-it's-a-coderef-else-retrieve
55           semantics are rather broken.  How do you pass a coderef as argument
56           to one of these?  It is on the TODO list to recognize code as
57           fundamental restricted type (analogous to INTEGER), which would add
58           in a *_invoke method.
59
60       copy
61             use Class::MethodMaker
62               [ copy => 'a' ];
63
64           The v2 method is the same as v1.
65
66       counter
67             use Class::MethodMaker
68               [ scalar => [{-type => Class::MethodMaker::Constants::INTEGER}, 'a'] ];
69
70       copy
71       deep_copy
72             use Class::MethodMaker
73               [ copy => [ -deep => 'a' ] ];
74
75       get_concat
76             use Class::MethodMaker
77               [ scalar => [{ -store_cb => sub {
78                                             defined $_[1] ? ( defined $_[3] ?
79                                                               "$_[3] $_[1]" : $_[1] )
80                                                           : undef;
81                                           }
82                            },
83                            'a' ]
84               ];
85
86       get_set
87             use Class::MethodMaker
88               [ scalar => 'a' ];
89
90       hash
91             use Class::MethodMaker
92               [ hash => 'a' ];
93
94       key_attrib
95           Although v1 calls will continue to work, this is not supported in
96           v2.
97
98       key_with_create
99           Although v1 calls will continue to work, this is not supported in
100           v2.
101
102       list
103             use Class::MethodMaker
104               [ list => 'a' ];
105
106           Note that the "*" method now sets the whole array if given
107           arguments.
108
109       method
110           See "code".
111
112       new
113             use Class::MethodMaker
114               [ new => 'a' ];
115
116       new_hash_init
117             use Class::MethodMaker
118               [ new => [ -hash => 'a' ] ];
119
120       new_hash_with_init
121             use Class::MethodMaker
122               [ new => [ -hash => -init => 'a' ] ];
123
124       new_with_args
125           Although v1 calls will continue to work, this is not supported in
126           v2, for it is a trivial application of "new_with_init".
127
128       new_with_init
129             use Class::MethodMaker
130               [ new => [ -init => 'a' ] ];
131
132       object
133             use Class::MethodMaker
134               [ scalar => [{ -type    => 'MyClass',
135                              -forward => [qw/ method1 method2 /] }, 'a' ]
136               ];
137
138       object_tie_hash
139             use Class::MethodMaker
140               [ hash => [{ -type      => 'MyClass',
141                            -forward   => [qw/ method1 method2 /],
142                            -tie_class => 'Tie::MyTie',
143                            -tie_args  => [qw/ foo bar baz /],
144                          }, 'a' ]
145               ];
146
147       object_tie_list
148             use Class::MethodMaker
149               [ array => [{ -type      => 'MyClass',
150                             -forward   => [qw/ method1 method2 /],
151                             -tie_class => 'Tie::MyTie',
152                             -tie_args  => [qw/ foo bar baz /],
153                           }, 'a' ]
154               ];
155
156       set_once
157             use Class::MethodMaker
158               [ scalar => [{ -store_cb => sub {
159                                             die "Already stored $_[3]"
160                                               if @_ > 3;
161                                           }
162                            },
163                            'a' ]
164               ];
165
166       set_once_static
167             use Class::MethodMaker
168               [ scalar => [{ -store_cb => sub {
169                                             die "Already stored $_[3]"
170                                               if @_ > 3;
171                                           },
172                              -static   => 1,
173                            },
174                            'a' ]
175               ];
176
177       singleton
178             use Class::MethodMaker
179               [ new => [ -singleton => -hash => -init => 'a' ] ];
180
181       static_get_set
182             use Class::MethodMaker
183               [ scalar => [ -static => 'a' ], ];
184
185       static_hash
186             use Class::MethodMaker
187               [ hash => [ -static => 'a' ], ];
188
189       static_list
190             use Class::MethodMaker
191               [ list => [ -static => 'a' ], ];
192
193       tie_hash
194             use Class::MethodMaker
195               [ hash => [ { -tie_class => 'MyTie',
196                             -tie_args  => [qw/ foo bar baz /],
197                           } => 'a' ], ];
198
199       tie_list
200             use Class::MethodMaker
201               [ array => [ { -tie_class => 'MyTie',
202                              -tie_args  => [qw/ foo bar baz /],
203                            } => 'a' ], ];
204
205       tie_scalar
206             use Class::MethodMaker
207               [ scalar => [ { -tie_class => 'MyTie',
208                               -tie_args  => [qw/ foo bar baz /],
209                             } => 'a' ], ];
210
211   Caveats & Expected Breakages
212       The following version 1 component (slot) types are not currently
213       supported in version 2:
214
215       grouped_fields
216       hash_of_lists
217       listed_attrib
218       struct
219

EXAMPLES

BUGS

REPORTING BUGS

223       Email the development mailing list
224       "class-mmaker-devel@lists.sourceforge.net".
225

AUTHOR

227       Martyn J. Pearce
228
230       Copyright (c) 2003, 2004 Martyn J. Pearce.  This program is free
231       software; you can redistribute it and/or modify it under the same terms
232       as Perl itself.
233

SEE ALSO

235perl v5.32.1                      2021-01-27   Class::MethodMaker::V1Compat(3)
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