This piece of code may serve as the base class for objects that need singleton methods (methods specific for this object and not for whole class). One can use it directly
or as base classmy $obj = DynObject->new(id => 'MyObj', action => sub{print "hi\n";}); print $obj->id, "\n"; $obj->action();
$obj = MyDyn->new(id => 'MyObj'); print $obj->id, "\n"; $obj->action(); package MyDyn; use base 'DynObject'; sub action { print "hi\n"; }
use strict; package DynObject; use Carp; my $counter = 0; sub new { my $class = shift; croak("The number of parameters must be even") unless @_ % 2 == 0; no strict 'refs'; my $type = ref $class; my $code; if(!$type) { $type = __PACKAGE__; $type .= "::obj@{[$counter++]}"; *{"${type}::ISA"} = [$class]; } for(my $i = 0; $i < @_; $i+=2) { croak("The method name '$_[$i]' is not a word") unless $_[$i] =~ /^\w+$/ && $_[$i] !~ /^\d+$/; if(ref $_[$i+1] eq 'CODE') { *{"${type}::$_[$i]"} = $_[$i+1]; } elsif(defined $_[$i+1] && !ref $_[$i+1]) { my $str = $_[$i+1]; *{"${type}::$_[$i]"} = sub{$str}; } else { delete ${"${type}::"}{$_[$i]}; } } return ref $class ? $class : bless [], $type; } sub DESTROY { my $obj = shift; my $type = ref $obj; $type =~ s/(\w+)$//; my $name = $1 . "::"; no strict 'refs'; delete ${$type}{$name}; } 1;
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Re: adding singleton methods to objects
by merlyn (Sage) on Jun 04, 2009 at 15:17 UTC |
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