1Clownfish::Obj(3)     User Contributed Perl Documentation    Clownfish::Obj(3)
2
3
4

NAME

6       Clownfish::Obj - Base class for all objects.
7

SYNOPSIS

9           package MyObj;
10           use base qw( Clownfish::Obj );
11
12           # Inside-out member var.
13           my %foo;
14
15           sub new {
16               my ( $class, %args ) = @_;
17               my $foo = delete $args{foo};
18               my $self = $class->SUPER::new(%args);
19               $foo{$$self} = $foo;
20               return $self;
21           }
22
23           sub get_foo {
24               my $self = shift;
25               return $foo{$$self};
26           }
27
28           sub DESTROY {
29               my $self = shift;
30               delete $foo{$$self};
31               $self->SUPER::DESTROY;
32           }
33

DESCRIPTION

35       Clownfish::Obj is the base class of the Clownfish object hierarchy.
36
37       From the standpoint of a Perl programmer, all classes are implemented
38       as blessed scalar references, with the scalar storing a pointer to a C
39       struct.
40
41   Subclassing
42       The recommended way to subclass Clownfish::Obj and its descendants is
43       to use the inside-out design pattern.  (See Class::InsideOut for an
44       introduction to inside-out techniques.)
45
46       Since the blessed scalar stores a C pointer value which is unique per-
47       object, $$self can be used as an inside-out ID.
48
49           # Accessor for 'foo' member variable.
50           sub get_foo {
51               my $self = shift;
52               return $foo{$$self};
53           }
54
55       Caveats:
56
57       •   Inside-out aficionados will have noted that the "cached scalar id"
58           stratagem recommended above isn't compatible with ithreads.
59
60       •   Overridden methods must not return undef unless the API specifies
61           that returning undef is permissible.
62

CONSTRUCTOR

64   new
65           my $self = $class->SUPER::new;
66
67       Abstract constructor -- must be invoked via a subclass.  Attempting to
68       instantiate objects of class "Clownfish::Obj" directly causes an error.
69
70       Takes no arguments; if any are supplied, an error will be reported.
71

ABSTRACT METHODS

73   clone
74           my $result = $obj->clone();
75
76       Return a clone of the object.
77
78   compare_to
79           my $int = $obj->compare_to($other);
80
81       Indicate whether one object is less than, equal to, or greater than
82       another.
83
84       •   other - Another Obj.
85
86       Returns: 0 if the objects are equal, a negative number if "self" is
87       less than "other", and a positive number if "self" is greater than
88       "other".
89

METHODS

91   to_perl
92           my $native = $obj->to_perl;
93
94       Tries to convert the object to its native Perl representation.
95
96   equals
97           my $bool = $obj->equals($other);
98
99       Indicate whether two objects are the same.  By default, compares the
100       memory address.
101
102       •   other - Another Obj.
103
104   DESTROY
105       All Clownfish classes implement a DESTROY method; if you override it in
106       a subclass, you must call "$self->SUPER::DESTROY" to avoid leaking
107       memory.
108
109   to_string
110           my $string = $obj->to_string();
111
112       Generic stringification: “ClassName@hex_mem_address”.
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116perl v5.36.0                      2023-01-20                 Clownfish::Obj(3)