1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
|
NAME
Object::Pad::ClassAttr::Struct - declare an Object::Pad class to be
struct-like
SYNOPSIS
use Object::Pad;
use Object::Pad::ClassAttr::Struct;
class Colour :Struct {
# These get :param :mutator automatically
field $red = 0;
field $green = 0;
field $blue = 0;
# Additional methods are still permitted
method lightness {
return ($red + $green + $blue) / 3;
}
}
my $cyan = Colour->new( green => 1, blue => 1 );
# A positional constructor is created automatically
my $white = Colour->new_values(1, 1, 1);
DESCRIPTION
This module provides a third-party class attribute for
Object::Pad-based classes, which applies some attributes automatically
to every field added to the class, as a convenient shortcut for making
structure-like classes.
CLASS ATTRIBUTES
:Struct
class Name :Struct ... { ... }
Automatically applies the :param and :mutator attributes to every field
defined on the class, meaning the constructor will accept parameters
for each field to initialise the value, and each field will have an
lvalue mutator method.
In addition, the class itself gains the :strict(params) attribute,
meaning the constructor will check parameter names and throw an
exception for unrecognised names.
Since version 0.04 a positional constructor class method called
new_values is also provided into the class, which takes a value for
every field positionally, in declared order.
$obj = ClassName->new_values($v1, $v2, $v3, ...);
This positional constructor must receive as many positional arguments
as there are fields in total in the class; even the optional ones. All
arguments are required here.
Since version 0.05 the following options are permitted inside the
attribute value parentheses:
:Struct(readonly)
Instances of this class do not permit fields to be modified after
construction. The accessor is created using the :reader field attribute
rather than :mutator.
AUTHOR
Paul Evans <leonerd@leonerd.org.uk>
|
