1MakeMethods::Standard::UHsaesrh(C3o)ntributed Perl DocumMeankteaMteitohnods::Standard::Hash(3)
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6 Class::MakeMethods::Standard::Hash - Standard hash methods
7
9 package MyObject;
10 use Class::MakeMethods::Standard::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 Standard::Hash suclass of MakeMethods provides a basic constructor
32 and accessors for blessed-hash object instances.
33 Calling Conventions
35 When you "use" this package, the method names you provide as arguments
36 cause subroutines to be generated and installed in your module.
37 See "Calling Conventions" in Class::MakeMethods::Standard for more
39 information.
40 Declaration Syntax
42 To declare methods, pass in pairs of a method-type name followed by one
43 or more method names.
44 Valid method-type names for this package are listed in "METHOD
46 GENERATOR TYPES".
47 See "Declaration Syntax" in Class::MakeMethods::Standard and "Parameter
49 Syntax" in Class::MakeMethods::Standard for more information.
50
52 new - Constructor
53 For each method name passed, returns a subroutine with the following
54 characteristics:
55 • Has a reference to a sample item to copy. This defaults to a
57 reference to an empty hash, but you may override this with the
58 "'defaults' =" hash_ref> method parameter.
59 • If called as a class method, makes a new hash and blesses it into
61 that class.
62 • If called on a hash-based instance, makes a copy of it and blesses
64 the copy into the same class as the original instance.
65 • If passed a list of key-value pairs, appends them to the new hash.
67 These arguments override any copied values, and later arguments
68 with the same name will override earlier ones.
69 • Returns the new instance.
71 Sample declaration and usage:
73 package MyObject;
75 use Class::MakeMethods::Standard::Hash (
76 new => 'new',
77 );
78 ...
79 # Bare constructor
81 my $empty = MyObject->new();
82 # Constructor with initial values
84 my $obj = MyObject->new( foo => 'Foozle', bar => 'Barbados' );
85 # Copy with overriding value
87 my $copy = $obj->new( bar => 'Bob' );
88 scalar - Instance Accessor
90 For each method name passed, uses a closure to generate a subroutine
91 with the following characteristics:
92 • Must be called on a hash-based instance.
94 • Has a specific hash key to use to access the related value for each
96 instance. This defaults to the method name, but you may override
97 this with the "'hash_key' =" string> method parameter.
98 • If called without any arguments returns the current value.
100 • If called with an argument, stores that as the value, and returns
102 it,
103 Sample declaration and usage:
105 package MyObject;
107 use Class::MakeMethods::Standard::Hash (
108 scalar => 'foo',
109 );
110 ...
111 # Store value
113 $obj->foo('Foozle');
114 # Retrieve value
116 print $obj->foo;
117 array - Instance Ref Accessor
119 For each method name passed, uses a closure to generate a subroutine
120 with the following characteristics:
121 • Must be called on a hash-based instance.
123 • Has a specific hash key to use to access the related value for each
125 instance. This defaults to the method name, but you may override
126 this with the "'hash_key' =" string> method parameter.
127 • The value for each instance will be a reference to an array (or
129 undef).
130 • If called without any arguments, returns the contents of the array
132 in list context, or an array reference in scalar context (or
133 undef).
134 • If called with a single array ref argument, sets the contents of
136 the array to match the contents of the provided one.
137 • If called with a single numeric argument, uses that argument as an
139 index to retrieve from the referenced array, and returns that value
140 (or undef).
141 • If called with a two arguments, the first undefined and the second
143 an array ref argument, uses that array's contents as a list of
144 indexes to return a slice of the referenced array.
145 • If called with a list of argument pairs, each with a numeric index
147 and an associated value, stores the value at the given index in the
148 referenced array. If the instance's value was previously undefined,
149 a new array is autovivified. The current value in each position
150 will be overwritten, and later arguments with the same index will
151 override earlier ones. Returns the current array-ref value.
152 • If called with a list of argument pairs, each with the first item
154 being a reference to an array of up to two numbers, loops over each
155 pair and uses those numbers to splice the value array.
156 The first controlling number is the position at which the splice
158 will begin. Zero will start before the first item in the list.
159 Negative numbers count backwards from the end of the array.
160 The second number is the number of items to be removed from the
162 list. If it is omitted, or undefined, or zero, no items are
163 removed. If it is a positive integer, that many items will be
164 returned.
165 If both numbers are omitted, or are both undefined, they default to
167 containing the entire value array.
168 If the second argument is undef, no values will be inserted; if it
170 is a non-reference value, that one value will be inserted; if it is
171 an array-ref, its values will be copied.
172 The method returns the items that removed from the array, if any.
174 Sample declaration and usage:
176 package MyObject;
178 use Class::MakeMethods::Standard::Hash (
179 array => 'bar',
180 );
181 ...
182 # Clear and set contents of list
184 print $obj->bar([ 'Spume', 'Frost' ] );
185 # Set values by position
187 $obj->bar(0 => 'Foozle', 1 => 'Bang!');
188 # Positions may be overwritten, and in any order
190 $obj->bar(2 => 'And Mash', 1 => 'Blah!');
191 # Retrieve value by position
193 print $obj->bar(1);
194 # Direct access to referenced array
196 print scalar @{ $obj->bar() };
197 There are also calling conventions for slice and splice operations:
199 # Retrieve slice of values by position
201 print join(', ', $obj->bar( undef, [0, 2] ) );
202 # Insert an item at position in the array
204 $obj->bar([3], 'Potatoes' );
205 # Remove 1 item from position 3 in the array
207 $obj->bar([3, 1], undef );
208 # Set a new value at position 2, and return the old value
210 print $obj->bar([2, 1], 'Froth' );
211 hash - Instance Ref Accessor
213 For each method name passed, uses a closure to generate a subroutine
214 with the following characteristics:
215 • Must be called on a hash-based instance.
217 • Has a specific hash key to use to access the related value for each
219 instance. This defaults to the method name, but you may override
220 this with the "'hash_key' =" string> method parameter.
221 • The value for each instance will be a reference to a hash (or
223 undef).
224 • If called without any arguments, returns the contents of the hash
226 in list context, or a hash reference in scalar context (or undef).
227 • If called with one non-ref argument, uses that argument as an index
229 to retrieve from the referenced hash, and returns that value (or
230 undef).
231 • If called with one array-ref argument, uses the contents of that
233 array to retrieve a slice of the referenced hash.
234 • If called with one hash-ref argument, sets the contents of the
236 referenced hash to match that provided.
237 • If called with a list of key-value pairs, stores the value under
239 the given key in the referenced hash. If the instance's value was
240 previously undefined, a new hash is autovivified. The current value
241 under each key will be overwritten, and later arguments with the
242 same key will override earlier ones. Returns the contents of the
243 hash in list context, or a hash reference in scalar context.
244 Sample declaration and usage:
246 package MyObject;
248 use Class::MakeMethods::Standard::Hash (
249 hash => 'baz',
250 );
251 ...
252 # Set values by key
254 $obj->baz('foo' => 'Foozle', 'bar' => 'Bang!');
255 # Values may be overwritten, and in any order
257 $obj->baz('broccoli' => 'Blah!', 'foo' => 'Fiddle');
258 # Retrieve value by key
260 print $obj->baz('foo');
261 # Retrive slice of values by position
263 print join(', ', $obj->baz( ['foo', 'bar'] ) );
264 # Direct access to referenced hash
266 print keys %{ $obj->baz() };
267 # Reset the hash contents to empty
269 %{ $obj->baz() } = ();
270 object - Instance Ref Accessor
272 For each method name passed, uses a closure to generate a subroutine
273 with the following characteristics:
274 • Must be called on a hash-based instance.
276 • Has a specific hash key to use to access the related value for each
278 instance. This defaults to the method name, but you may override
279 this with the "'hash_key' =" string> method parameter.
280 • The value for each instance will be a reference to an object (or
282 undef).
283 • If called without any arguments returns the current value.
285 • If called with an argument, stores that as the value, and returns
287 it,
288 Sample declaration and usage:
290 package MyObject;
292 use Class::MakeMethods::Standard::Hash (
293 object => 'foo',
294 );
295 ...
296 # Store value
298 $obj->foo( Foozle->new() );
299 # Retrieve value
301 print $obj->foo;
302
304 See Class::MakeMethods for general information about this distribution.
305 See Class::MakeMethods::Standard for more about this family of
307 subclasses.
308perl v5.36.0 2023-01-20 MakeMethods::Standard::Hash(3)