1MakeMethods::Composite:U:sHearshC(o3n)tributed Perl DocuMmaeknetMaettihoonds::Composite::Hash(3)
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6 Class::MakeMethods::Composite::Hash - Composite hash methods
7
9 package MyObject;
10 use Class::MakeMethods::Composite::Hash (
11 new => 'new',
12 scalar => [ 'foo', 'bar' ],
13 array => 'my_list',
14 hash => 'my_index',
15 );
16 ...
17 my $obj = MyObject->new( foo => 'Foozle' );
19 print $obj->foo();
20 $obj->bar('Barbados');
22 print $obj->bar();
23 $obj->my_list(0 => 'Foozle', 1 => 'Bang!');
25 print $obj->my_list(1);
26 $obj->my_index('broccoli' => 'Blah!', 'foo' => 'Fiddle');
28 print $obj->my_index('foo');
29
31 The Composite::Hash suclass of MakeMethods provides a basic constructor
32 and accessors for blessed-hash object instances.
33 Class::MakeMethods Calling Interface
35 When you "use" this package, the method declarations you provide as
37 arguments cause subroutines to be generated and installed in your mod‐
38 ule.
39 You can also omit the arguments to "use" and instead make methods at
41 runtime by passing the declarations to a subsequent call to "make()".
42 You may include any number of declarations in each call to "use" or
44 "make()". If methods with the same name already exist, earlier calls to
45 "use" or "make()" win over later ones, but within each call, later dec‐
46 larations superceed earlier ones.
47 You can install methods in a different package by passing "-TargetClass
49 => package" as your first arguments to "use" or "make".
50 See Class::MakeMethods for more details.
52 Class::MakeMethods::Basic Declaration Syntax
54 The following types of Basic declarations are supported:
56 · generator_type => "method_name"
58 · generator_type => "name_1 name_2..."
60 · generator_type => [ "name_1", "name_2", ...]
62 See the "METHOD GENERATOR TYPES" section below for a list of the sup‐
64 ported values of generator_type.
65 For each method name you provide, a subroutine of the indicated type
67 will be generated and installed under that name in your module.
68 Method names should start with a letter, followed by zero or more let‐
70 ters, numbers, or underscores.
71 Class::MakeMethods::Composite Declaration Syntax
73 The Composite syntax also provides several ways to optionally associate
75 a hash of additional parameters with a given method name.
76 · generator_type => [ "name_1" => { param=>value... }, ... ]
78 A hash of parameters to use just for this method name.
80 (Note: to prevent confusion with self-contained definition hashes,
82 described below, parameter hashes following a method name must not
83 contain the key 'name'.)
84 · generator_type => [ [ "name_1", "name_2", ... ] => {
86 param=>value... } ]
87 Each of these method names gets a copy of the same set of parame‐
89 ters.
90 · generator_type => [ { "name"=>"name_1", param=>value... }, ... ]
92 By including the reserved parameter "name", you create a self-con‐
94 tained declaration with that name and any associated hash values.
95 Basic declarations, as described above, are given an empty parameter
97 hash.
98
100 new - Constructor
101 For each method name passed, returns a subroutine with the following
103 characteristics:
104 · Has a reference to a sample item to copy. This defaults to a refer‐
106 ence to an empty hash, but you may override this with the
107 "'defaults' => hash_ref" method parameter.
108 · If called as a class method, makes a new hash and blesses it into
110 that class.
111 · If called on a hash-based instance, makes a copy of it and blesses
113 the copy into the same class as the original instance.
114 · If passed a list of key-value pairs, appends them to the new hash.
116 These arguments override any copied values, and later arguments
117 with the same name will override earlier ones.
118 · Returns the new instance.
120 Sample declaration and usage:
122 package MyObject;
124 use Class::MakeMethods::Composite::Hash (
125 new => 'new',
126 );
127 ...
128 # Bare constructor
130 my $empty = MyObject->new();
131 # Constructor with initial values
133 my $obj = MyObject->new( foo => 'Foozle', bar => 'Barbados' );
134 # Copy with overriding value
136 my $copy = $obj->new( bar => 'Bob' );
137 new --with_values - Constructor
139 For each method name passed, returns a subroutine with the following
141 characteristics:
142 · May be called as a class method, or (equivalently) on any existing
144 object of that class.
145 · Creates a hash, blesses it into the class, and returns the new
147 instance.
148 · If no arguments are provided, the returned hash will be empty. If
150 passed a single hash-ref argument, copies its contents into the new
151 hash. If called with multiple arguments, treats them as key-value
152 pairs, and copies them into the new hash. (Note that this is a
153 "shallow" copy, not a "deep" clone.)
154 scalar - Instance Accessor
156 For each method name passed, uses a closure to generate a subroutine
158 with the following characteristics:
159 · Must be called on a hash-based instance.
161 · Has a specific hash key to use to access the related value for each
163 instance. This defaults to the method name, but you may override
164 this with the "'hash_key' =" string> method parameter.
165 · If called without any arguments returns the current value.
167 · If called with an argument, stores that as the value, and returns
169 it.
170 · If called with multiple arguments, stores a reference to a new
172 array with those arguments as contents, and returns that array ref‐
173 erence.
174 Sample declaration and usage:
176 package MyObject;
178 use Class::MakeMethods::Composite::Hash (
179 scalar => 'foo',
180 );
181 ...
182 # Store value
184 $obj->foo('Foozle');
185 # Retrieve value
187 print $obj->foo;
188 array - Instance Ref Accessor
190 For each method name passed, uses a closure to generate a subroutine
192 with the following characteristics:
193 · Must be called on a hash-based instance.
195 · Has a specific hash key to use to access the related value for each
197 instance. This defaults to the method name, but you may override
198 this with the "'hash_key' =" string> method parameter.
199 · The value for each instance will be a reference to an array (or
201 undef).
202 · If called without any arguments, returns the current array-ref
204 value (or undef).
205 · If called with a single non-ref argument, uses that argument as an
207 index to retrieve from the referenced array, and returns that value
208 (or undef).
209 · If called with a single array ref argument, uses that list to
211 return a slice of the referenced array.
212 · If called with a list of argument pairs, each with a non-ref index
214 and an associated value, stores the value at the given index in the
215 referenced array. If the instance's value was previously undefined,
216 a new array is autovivified. The current value in each position
217 will be overwritten, and later arguments with the same index will
218 override earlier ones. Returns the current array-ref value.
219 · If called with a list of argument pairs, each with the first item
221 being a reference to an array of up to two numbers, loops over each
222 pair and uses those numbers to splice the value array.
223 The first controlling number is the position at which the splice
225 will begin. Zero will start before the first item in the list. Neg‐
226 ative numbers count backwards from the end of the array.
227 The second number is the number of items to be removed from the
229 list. If it is omitted, or undefined, or zero, no items are
230 removed. If it is a positive integer, that many items will be
231 returned.
232 If both numbers are omitted, or are both undefined, they default to
234 containing the entire value array.
235 If the second argument is undef, no values will be inserted; if it
237 is a non-reference value, that one value will be inserted; if it is
238 an array-ref, its values will be copied.
239 The method returns the items that removed from the array, if any.
241 Sample declaration and usage:
243 package MyObject;
245 use Class::MakeMethods::Composite::Hash (
246 array => 'bar',
247 );
248 ...
249 # Clear and set contents of list
251 print $obj->bar([ 'Spume', 'Frost' ] );
252 # Set values by position
254 $obj->bar(0 => 'Foozle', 1 => 'Bang!');
255 # Positions may be overwritten, and in any order
257 $obj->bar(2 => 'And Mash', 1 => 'Blah!');
258 # Retrieve value by position
260 print $obj->bar(1);
261 # Direct access to referenced array
263 print scalar @{ $obj->bar() };
264 There are also calling conventions for slice and splice operations:
266 # Retrieve slice of values by position
268 print join(', ', $obj->bar( undef, [0, 2] ) );
269 # Insert an item at position in the array
271 $obj->bar([3], 'Potatoes' );
272 # Remove 1 item from position 3 in the array
274 $obj->bar([3, 1], undef );
275 # Set a new value at position 2, and return the old value
277 print $obj->bar([2, 1], 'Froth' );
278 hash - Instance Ref Accessor
280 For each method name passed, uses a closure to generate a subroutine
282 with the following characteristics:
283 · Must be called on a hash-based instance.
285 · Has a specific hash key to use to access the related value for each
287 instance. This defaults to the method name, but you may override
288 this with the "'hash_key' =" string> method parameter.
289 · The value for each instance will be a reference to a hash (or
291 undef).
292 · If called without any arguments, returns the contents of the hash
294 in list context, or a hash reference in scalar context (or undef).
295 · If called with one non-ref argument, uses that argument as an index
297 to retrieve from the referenced hash, and returns that value (or
298 undef).
299 · If called with one array-ref argument, uses the contents of that
301 array to retrieve a slice of the referenced hash.
302 · If called with one hash-ref argument, sets the contents of the ref‐
304 erenced hash to match that provided.
305 · If called with a list of key-value pairs, stores the value under
307 the given key in the referenced hash. If the instance's value was
308 previously undefined, a new hash is autovivified. The current value
309 under each key will be overwritten, and later arguments with the
310 same key will override earlier ones. Returns the contents of the
311 hash in list context, or a hash reference in scalar context.
312 Sample declaration and usage:
314 package MyObject;
316 use Class::MakeMethods::Composite::Hash (
317 hash => 'baz',
318 );
319 ...
320 # Set values by key
322 $obj->baz('foo' => 'Foozle', 'bar' => 'Bang!');
323 # Values may be overwritten, and in any order
325 $obj->baz('broccoli' => 'Blah!', 'foo' => 'Fiddle');
326 # Retrieve value by key
328 print $obj->baz('foo');
329 # Retrive slice of values by position
331 print join(', ', $obj->baz( ['foo', 'bar'] ) );
332 # Direct access to referenced hash
334 print keys %{ $obj->baz() };
335 # Reset the hash contents to empty
337 @{ $obj->baz() } = ();
338 object - Instance Ref Accessor
340 For each method name passed, uses a closure to generate a subroutine
342 with the following characteristics:
343 · Must be called on a hash-based instance.
345 · Has a specific hash key to use to access the related value for each
347 instance. This defaults to the method name, but you may override
348 this with the "'hash_key' =" string> method parameter.
349 · The value for each instance will be a reference to an object (or
351 undef).
352 · If called without any arguments returns the current value.
354 · If called with an argument, stores that as the value, and returns
356 it,
357 Sample declaration and usage:
359 package MyObject;
361 use Class::MakeMethods::Composite::Hash (
362 object => 'foo',
363 );
364 ...
365 # Store value
367 $obj->foo( Foozle->new() );
368 # Retrieve value
370 print $obj->foo;
371
373 See Class::MakeMethods for general information about this distribution.
374 See Class::MakeMethods::Composite for more about this family of sub‐
376 classes.
377perl v5.8.8 2004-09-06 MakeMethods::Composite::Hash(3)