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
36 arguments cause subroutines to be generated and installed in your
37 module.
38 You can also omit the arguments to "use" and instead make methods at
40 runtime by passing the declarations to a subsequent call to "make()".
41 You may include any number of declarations in each call to "use" or
43 "make()". If methods with the same name already exist, earlier calls to
44 "use" or "make()" win over later ones, but within each call, later
45 declarations superceed earlier ones.
46 You can install methods in a different package by passing "-TargetClass
48 => package" as your first arguments to "use" or "make".
49 See Class::MakeMethods for more details.
51 Class::MakeMethods::Basic Declaration Syntax
53 The following types of Basic declarations are supported:
54 • generator_type => "method_name"
56 • generator_type => "name_1 name_2..."
58 • generator_type => [ "name_1", "name_2", ...]
60 See the "METHOD GENERATOR TYPES" section below for a list of the
62 supported values of generator_type.
63 For each method name you provide, a subroutine of the indicated type
65 will be generated and installed under that name in your module.
66 Method names should start with a letter, followed by zero or more
68 letters, numbers, or underscores.
69 Class::MakeMethods::Composite Declaration Syntax
71 The Composite syntax also provides several ways to optionally associate
72 a hash of additional parameters with a given method name.
73 • generator_type => [ "name_1" => { param=>value... }, ... ]
75 A hash of parameters to use just for this method name.
77 (Note: to prevent confusion with self-contained definition hashes,
79 described below, parameter hashes following a method name must not
80 contain the key 'name'.)
81 • generator_type => [ [ "name_1", "name_2", ... ] => {
83 param=>value... } ]
84 Each of these method names gets a copy of the same set of
86 parameters.
87 • generator_type => [ { "name"=>"name_1", param=>value... }, ... ]
89 By including the reserved parameter "name", you create a self-
91 contained declaration with that name and any associated hash
92 values.
93 Basic declarations, as described above, are given an empty parameter
95 hash.
96
98 new - Constructor
99 For each method name passed, returns a subroutine with the following
100 characteristics:
101 • Has a reference to a sample item to copy. This defaults to a
103 reference to an empty hash, but you may override this with the
104 "'defaults' => hash_ref" method parameter.
105 • If called as a class method, makes a new hash and blesses it into
107 that class.
108 • If called on a hash-based instance, makes a copy of it and blesses
110 the copy into the same class as the original instance.
111 • If passed a list of key-value pairs, appends them to the new hash.
113 These arguments override any copied values, and later arguments
114 with the same name will override earlier ones.
115 • Returns the new instance.
117 Sample declaration and usage:
119 package MyObject;
121 use Class::MakeMethods::Composite::Hash (
122 new => 'new',
123 );
124 ...
125 # Bare constructor
127 my $empty = MyObject->new();
128 # Constructor with initial values
130 my $obj = MyObject->new( foo => 'Foozle', bar => 'Barbados' );
131 # Copy with overriding value
133 my $copy = $obj->new( bar => 'Bob' );
134 new --with_values - Constructor
136 For each method name passed, returns a subroutine with the following
137 characteristics:
138 • May be called as a class method, or (equivalently) on any existing
140 object of that class.
141 • Creates a hash, blesses it into the class, and returns the new
143 instance.
144 • If no arguments are provided, the returned hash will be empty. If
146 passed a single hash-ref argument, copies its contents into the new
147 hash. If called with multiple arguments, treats them as key-value
148 pairs, and copies them into the new hash. (Note that this is a
149 "shallow" copy, not a "deep" clone.)
150 scalar - Instance Accessor
152 For each method name passed, uses a closure to generate a subroutine
153 with the following characteristics:
154 • Must be called on a hash-based instance.
156 • Has a specific hash key to use to access the related value for each
158 instance. This defaults to the method name, but you may override
159 this with the "'hash_key' =" string> method parameter.
160 • If called without any arguments returns the current value.
162 • If called with an argument, stores that as the value, and returns
164 it.
165 • If called with multiple arguments, stores a reference to a new
167 array with those arguments as contents, and returns that array
168 reference.
169 Sample declaration and usage:
171 package MyObject;
173 use Class::MakeMethods::Composite::Hash (
174 scalar => 'foo',
175 );
176 ...
177 # Store value
179 $obj->foo('Foozle');
180 # Retrieve value
182 print $obj->foo;
183 array - Instance Ref Accessor
185 For each method name passed, uses a closure to generate a subroutine
186 with the following characteristics:
187 • Must be called on a hash-based instance.
189 • Has a specific hash key to use to access the related value for each
191 instance. This defaults to the method name, but you may override
192 this with the "'hash_key' =" string> method parameter.
193 • The value for each instance will be a reference to an array (or
195 undef).
196 • If called without any arguments, returns the current array-ref
198 value (or undef).
199 • If called with a single non-ref argument, uses that argument as an
201 index to retrieve from the referenced array, and returns that value
202 (or undef).
203 • If called with a single array ref argument, uses that list to
205 return a slice of the referenced array.
206 • If called with a list of argument pairs, each with a non-ref index
208 and an associated value, stores the value at the given index in the
209 referenced array. If the instance's value was previously undefined,
210 a new array is autovivified. The current value in each position
211 will be overwritten, and later arguments with the same index will
212 override earlier ones. Returns the current array-ref value.
213 • If called with a list of argument pairs, each with the first item
215 being a reference to an array of up to two numbers, loops over each
216 pair and uses those numbers to splice the value array.
217 The first controlling number is the position at which the splice
219 will begin. Zero will start before the first item in the list.
220 Negative numbers count backwards from the end of the array.
221 The second number is the number of items to be removed from the
223 list. If it is omitted, or undefined, or zero, no items are
224 removed. If it is a positive integer, that many items will be
225 returned.
226 If both numbers are omitted, or are both undefined, they default to
228 containing the entire value array.
229 If the second argument is undef, no values will be inserted; if it
231 is a non-reference value, that one value will be inserted; if it is
232 an array-ref, its values will be copied.
233 The method returns the items that removed from the array, if any.
235 Sample declaration and usage:
237 package MyObject;
239 use Class::MakeMethods::Composite::Hash (
240 array => 'bar',
241 );
242 ...
243 # Clear and set contents of list
245 print $obj->bar([ 'Spume', 'Frost' ] );
246 # Set values by position
248 $obj->bar(0 => 'Foozle', 1 => 'Bang!');
249 # Positions may be overwritten, and in any order
251 $obj->bar(2 => 'And Mash', 1 => 'Blah!');
252 # Retrieve value by position
254 print $obj->bar(1);
255 # Direct access to referenced array
257 print scalar @{ $obj->bar() };
258 There are also calling conventions for slice and splice operations:
260 # Retrieve slice of values by position
262 print join(', ', $obj->bar( undef, [0, 2] ) );
263 # Insert an item at position in the array
265 $obj->bar([3], 'Potatoes' );
266 # Remove 1 item from position 3 in the array
268 $obj->bar([3, 1], undef );
269 # Set a new value at position 2, and return the old value
271 print $obj->bar([2, 1], 'Froth' );
272 hash - Instance Ref Accessor
274 For each method name passed, uses a closure to generate a subroutine
275 with the following characteristics:
276 • Must be called on a hash-based instance.
278 • Has a specific hash key to use to access the related value for each
280 instance. This defaults to the method name, but you may override
281 this with the "'hash_key' =" string> method parameter.
282 • The value for each instance will be a reference to a hash (or
284 undef).
285 • If called without any arguments, returns the contents of the hash
287 in list context, or a hash reference in scalar context (or undef).
288 • If called with one non-ref argument, uses that argument as an index
290 to retrieve from the referenced hash, and returns that value (or
291 undef).
292 • If called with one array-ref argument, uses the contents of that
294 array to retrieve a slice of the referenced hash.
295 • If called with one hash-ref argument, sets the contents of the
297 referenced hash to match that provided.
298 • If called with a list of key-value pairs, stores the value under
300 the given key in the referenced hash. If the instance's value was
301 previously undefined, a new hash is autovivified. The current value
302 under each key will be overwritten, and later arguments with the
303 same key will override earlier ones. Returns the contents of the
304 hash in list context, or a hash reference in scalar context.
305 Sample declaration and usage:
307 package MyObject;
309 use Class::MakeMethods::Composite::Hash (
310 hash => 'baz',
311 );
312 ...
313 # Set values by key
315 $obj->baz('foo' => 'Foozle', 'bar' => 'Bang!');
316 # Values may be overwritten, and in any order
318 $obj->baz('broccoli' => 'Blah!', 'foo' => 'Fiddle');
319 # Retrieve value by key
321 print $obj->baz('foo');
322 # Retrive slice of values by position
324 print join(', ', $obj->baz( ['foo', 'bar'] ) );
325 # Direct access to referenced hash
327 print keys %{ $obj->baz() };
328 # Reset the hash contents to empty
330 @{ $obj->baz() } = ();
331 object - Instance Ref Accessor
333 For each method name passed, uses a closure to generate a subroutine
334 with the following characteristics:
335 • Must be called on a hash-based instance.
337 • Has a specific hash key to use to access the related value for each
339 instance. This defaults to the method name, but you may override
340 this with the "'hash_key' =" string> method parameter.
341 • The value for each instance will be a reference to an object (or
343 undef).
344 • If called without any arguments returns the current value.
346 • If called with an argument, stores that as the value, and returns
348 it,
349 Sample declaration and usage:
351 package MyObject;
353 use Class::MakeMethods::Composite::Hash (
354 object => 'foo',
355 );
356 ...
357 # Store value
359 $obj->foo( Foozle->new() );
360 # Retrieve value
362 print $obj->foo;
363
365 See Class::MakeMethods for general information about this distribution.
366 See Class::MakeMethods::Composite for more about this family of
368 subclasses.
369perl v5.34.0 2021-07-22 MakeMethods::Composite::Hash(3)