1Class::MethodMaker::arrUasye(r3)Contributed Perl DocumenCtlaatsiso:n:MethodMaker::array(3)
2
6 Class::Method::array - Create methods for handling an array value.
7
9 use Class::MethodMaker
10 [ array => [qw/ x /] ];
11 $instance->x; # empty
13 $instance->x(1, 1, 2, 3, 5, 8);
14 $instance->x_count == 6; # true
15 $instance->x = (13, 21, 34);
16 $instance->x_index(1) == 21; # true
17
19 Creates methods to handle array values in an object. For a component
20 named "x", by default creates methods "x", "x_reset", "x_clear",
21 "x_isset", "x_count", "x_index", "x_push", "x_pop", "x_unshift",
22 "x_shift", "x_splice".
23 Methods available are:
25 "*"
27 Created by default. This method returns the list of values stored in
29 the slot. If any arguments are provided to this method, they replace
30 the current list contents. In an array context it returns the values
31 as an array and in a scalar context as a reference to an array. Note
32 that this reference is no longer a direct reference to the storage, in
33 contrast to Class::MethodMaker v1. This is to protect encapsulation.
34 See x_ref if you need that functionality (and are prepared to take the
35 associated risk.) This function no longer auto-expands arrayrefs input
36 as arguments, since that makes it awkward to set individual values to
37 arrayrefs. See x_setref for that functionality.
38 If a default value is in force, then that value will be auto-vivified
40 (and therefore set) for each otherwise unset (not not defined) value up
41 to the array max (so new items will not be appended)
42 *_reset
44 Created by default. Called without an argument, this resets the
46 component as a whole; deleting any associated storage, and returning
47 the component to its default state. Normally, this means that *_isset
48 will return false, and "*" will return undef. If "-default" is in
49 effect, then the component will be set to the default value, and
50 *_isset will return true. If "-default_ctor" is in effect, then the
51 default subr will be invoked, and its return value used to set the
52 value of the component, and *_isset will return true.
53 If called with arguments, these arguments are treated as indexes into
55 the component, and the individual elements thus referenced are reset
56 (their storage deleted, so that *_isset(n) will return false for
57 appropriate n, except where "-default" or "-default_ctor" are in force,
58 as above). As with perl arrays, resetting the highest set value
59 implicitly decreases the count (but x_reset(n) never unsets the
60 aggregate itself, even if all the elements are not set).
61 *_clear
63 package MyClass;
65 use Class::MethodMaker
66 [ scalar => [{'*_clear' => '*_clear'}, 'a'],
67 new => new, ];
68 package main;
70 my $m = MyClass->new;
71 $m->a(5);
72 $a = $m->a; # 5
73 $x = $m->a_isset; # true
74 $m->a_clear;
75 $a = $m->a; # *undef*
76 $x = $m->a_isset; # true
77 Created on request. A shorthand for setting to undef. Note that the
79 component will be set to undef, not reset, so *_isset will return true.
80 *_isset
82 Created by default. Whether the component is currently set. This is
84 different from being defined; initially, the component is not set (and
85 if read, will return undef); it can be set to undef (which is a set
86 value, which also returns undef). Having been set, the only way to
87 unset the component is with <*_reset>.
88 If a default value is in effect, then <*_isset> will always return
90 true.
91 "*_isset()" tests the component as a whole. *_isset(a) tests the
93 element indexed by a. "*_isset(a,b)" tests the elements indexed by a,
94 b, and returns the logical conjunction (and) of the tests.
95 *_count
97 Created by default. Returns the number of elements in this component.
99 This is not affected by presence (or lack) of a "default" (or
100 "default_ctor"). Returns "undef" if whole component not set (as per
101 *_isset).
102 *_index
104 Created by default. Takes a list of indices, returns a list of the
106 corresponding values.
107 If a default (or a default ctor) is in force, then a lookup by index
109 will vivify & set to the default the respective elements (and therefore
110 the aggregate data-structure also, if it's not already).
111 Beware of a bug in perl 5.6.1 that will sometimes invent values in
113 previously unset slots of arrays that previously contained a value.
114 So, vivifying a value (e.g. by x_index(2)) where x_index(1) was
115 previously unset might cause x_index(1) to be set spuriously. This is
116 fixed in 5.8.0.
117 *_push
119 Created by default. Push item(s) onto the end of the list. No return
121 value.
122 *_pop
124 Created by default. Given a number, pops that many items off the end of
126 the list, and returns them (as a ref in scalar context, as a list in
127 list context). Without an arg, always returns a single element. Given
128 a number, returns them in array order (not in reverse order as multiple
129 pops would).
130 *_unshift
132 Created by default. Push item(s) onto the start of the list. No return
134 value.
135 *_shift
137 Created by default. Given a number, shifts that many items off the
139 start of the list, and returns them (as a ref in scalar context, as a
140 list in list context). Without an arg, always returns a single
141 element. Given a number, returns them in array order.
142 *_splice
144 Created by default. Arguments as for perldoc perlfunc splice. Returns
146 an arrayref in scalar context (even if a single item is spliced), and a
147 list in list context.
148 *_get
150 Created on request. Retrieves the value of the component without
152 setting (ignores any arguments passed).
153 *_set
155 @n = $x->a; # (1,2,3)
157 $x->a_set(1=>4,3=>7);
158 @n = $x->a; # (1,4,3,7)
159 Created by default. Takes a list, treated as pairs of index => value;
161 each given index is set to the corresponding value. No return.
162 If two arguments are given, of which the first is an arrayref, then it
164 is treated as a list of indices of which the second argument (which
165 must also be an arrayref) are the corresponding values. Thus the
166 following two commands are equivalent:
167 $x->a_set(1=>4,3=>7);
169 $x->a_set([1,3],[4,7]);
170perl v5.28.1 2019-02-02 Class::MethodMaker::array(3)