How can I change the definition of this method on this object only, at runtime, after the instance's creation?
Since calling a method is really just calling a subroutine with a bit of extra magic this isn't easily doable, as if you change the method that a given object calls, it'll be changed for any other objects that access that method. Off the top of my head you could do something like this
sub fudge_method {
my($obj, $method, $sub) = @_;
## you'll probably want to extend this for other data types
$_[0] = bless {%$obj}, init_class(ref $obj, $method, $sub);
}
{
my $cnt = 0;
sub init_class {
my($class,$method,$sub) = @_;
my $name = $class."::_tmp".$cnt++;
no strict 'refs';
@{$name."::ISA"} = $class;
*{$name."::$method"} = $sub;
return $name;
}
}
{
package foo;
sub new { bless {@_[1 .. $#_]}, shift }
sub dostuff { print "I'm doing stuff [", %{$_[0]}, "]\n" }
}
my $o = foo->new(field => 'var');
print "pre fudge - ";
$o->dostuff();
fudge_method($o, 'dostuff', sub {
print "I've done stuff [", %{$_[0]}, "]\n";
});
print "post fudge - ";
$o->dostuff();
my $o2 = foo->new(this => 'that');
print "new object - ";
$o2->dostuff();
__output__
pre fudge - I'm doing stuff [fieldvar]
post fudge - I've done stuff [fieldvar]
new object - I'm doing stuff [thisthat]
That code is rather hackish (only deals with
blessed hashes for exampple) but hopefully it'll give you a start on what you want achieved.
HTH
_________
broquaint
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