1Class::MethodMaker::V1CUosmepratC(o3n)tributed Perl DocuCmleanstsa:t:iMoenthodMaker::V1Compat(3)
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6 Class::MethodMaker::V1Compat - V1 compatibility code for C::MM
7
9 This class is for internal implementation only. It is not a public
10 API.
11
13 Class::MethodMaker version 2 strives for backward-compatiblity with
14 version 1 as far as possible. That is to say, classes built with ver‐
15 sion 1 should work with few if any changes. However, the calling con‐
16 ventions for building new classes are significantly different: this is
17 necessary to achieve a greater consistency of arguments.
18 Version 2 takes all arguments within a single arrayref:
20 use Class::MethodMaker
22 [ scalar => 'a' ];
23 If arguments are presented as a list, then Class::MethodMaker assumes
25 that this is a version 1 call, and acts accordingly. Version 1 argu‐
26 ments are passed and internally rephrased to version 2 arguments, and
27 passed off to the version 2 engine. Thus, the majority of version 1
28 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 Version 2 Implementations
35 The nearest equivalent to each 1 component (slot) available in version
37 2 is shown below using the indicated data-structures & options to cre‐
38 ate a component called "a" that mimicks the V1 component behaviour as
39 closely as possible:
40 abstract
42 use Class::MethodMaker
43 [ abstract => 'a' ];
44 boolean
46 Boolean is available as a backwards compatiblity hack, but there is
47 currently no V2 equivalent. It is likely that some replacement
48 mechanism will be introduced in the future, but that it will be
49 incompatible with the version 1 boolean.
50 code
52 use Class::MethodMaker
53 [ scalar => 'a' ];
54 Let's face it, the v1 store-if-it's-a-coderef-else-retrieve seman‐
56 tics are rather broken. How do you pass a coderef as argument to
57 one of these? It is on the TODO list to recognize code as funda‐
58 mental restricted type (analogous to INTEGER), which would add in a
59 *_invoke method.
60 copy
62 use Class::MethodMaker
63 [ copy => 'a' ];
64 The v2 method is the same as v1.
66 counter
68 use Class::MethodMaker
69 [ scalar => [{-type => Class::MethodMaker::Constants::INTEGER}, 'a'] ];
70 copy
72 deep_copy
73 use Class::MethodMaker
74 [ copy => [ -deep => 'a' ] ];
75 get_concat
77 use Class::MethodMaker
78 [ scalar => [{ -store_cb => sub {
79 defined $_[1] ? ( defined $_[3] ?
80 "$_[3] $_[1]" : $_[1] )
81 : undef;
82 }
83 },
84 'a' ]
85 ];
86 get_set
88 use Class::MethodMaker
89 [ scalar => 'a' ];
90 hash
92 use Class::MethodMaker
93 [ hash => 'a' ];
94 key_attrib
96 Although v1 calls will continue to work, this is not supported in
97 v2.
98 key_with_create
100 Although v1 calls will continue to work, this is not supported in
101 v2.
102 list
104 use Class::MethodMaker
105 [ list => 'a' ];
106 Note that the "*" method now sets the whole array if given argu‐
108 ments.
109 method
111 See "code".
112 new
114 use Class::MethodMaker
115 [ new => 'a' ];
116 new_hash_init
118 use Class::MethodMaker
119 [ new => [ -hash => 'a' ] ];
120 new_hash_with_init
122 use Class::MethodMaker
123 [ new => [ -hash => -init => 'a' ] ];
124 new_with_args
126 Although v1 calls will continue to work, this is not supported in
127 v2, for it is a trivial application of "new_with_init".
128 new_with_init
130 use Class::MethodMaker
131 [ new => [ -init => 'a' ] ];
132 object
134 use Class::MethodMaker
135 [ scalar => [{ -type => 'MyClass',
136 -forward => [qw/ method1 method2 /] }, 'a' ]
137 ];
138 object_tie_hash
140 use Class::MethodMaker
141 [ hash => [{ -type => 'MyClass',
142 -forward => [qw/ method1 method2 /],
143 -tie_class => 'Tie::MyTie',
144 -tie_args => [qw/ foo bar baz /],
145 }, 'a' ]
146 ];
147 object_tie_list
149 use Class::MethodMaker
150 [ array => [{ -type => 'MyClass',
151 -forward => [qw/ method1 method2 /],
152 -tie_class => 'Tie::MyTie',
153 -tie_args => [qw/ foo bar baz /],
154 }, 'a' ]
155 ];
156 set_once
158 use Class::MethodMaker
159 [ scalar => [{ -store_cb => sub {
160 die "Already stored $_[3]"
161 if @_ > 3;
162 }
163 },
164 'a' ]
165 ];
166 set_once_static
168 use Class::MethodMaker
169 [ scalar => [{ -store_cb => sub {
170 die "Already stored $_[3]"
171 if @_ > 3;
172 },
173 -static => 1,
174 },
175 'a' ]
176 ];
177 singleton
179 use Class::MethodMaker
180 [ new => [ -singleton => -hash => -init => 'a' ] ];
181 static_get_set
183 use Class::MethodMaker
184 [ scalar => [ -static => 'a' ], ];
185 static_hash
187 use Class::MethodMaker
188 [ hash => [ -static => 'a' ], ];
189 static_list
191 use Class::MethodMaker
192 [ list => [ -static => 'a' ], ];
193 tie_hash
195 use Class::MethodMaker
196 [ hash => [ { -tie_class => 'MyTie',
197 -tie_args => [qw/ foo bar baz /],
198 } => 'a' ], ];
199 tie_list
201 use Class::MethodMaker
202 [ array => [ { -tie_class => 'MyTie',
203 -tie_args => [qw/ foo bar baz /],
204 } => 'a' ], ];
205 tie_scalar
207 use Class::MethodMaker
208 [ scalar => [ { -tie_class => 'MyTie',
209 -tie_args => [qw/ foo bar baz /],
210 } => 'a' ], ];
211 Caveats & Expected Breakages
213 The following version 1 component (slot) types are not currently sup‐
215 ported in version 2:
216 grouped_fields
218 hash_of_lists
219 listed_attrib
220 struct
221
223
226
229 Email the development mailing list "class-mmaker-devel@lists.source‐
230 forge.net".
231
233 Martyn J. Pearce
234
236 Copyright (c) 2003, 2004 Martyn J. Pearce. This program is free soft‐
237 ware; you can redistribute it and/or modify it under the same terms as
238 Perl itself.
239
241perl v5.8.8 2005-11-26 Class::MethodMaker::V1Compat(3)