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There is probably a better way to do this. (Likely on CPAN.) Plus this is slow. But here is a very simple implementation of a different inheritance scheme than the one that Perl uses. This is based on each object being its own class. Call the def method to add new methods to the object. Call new to generate an object that inherits from the parent. Call "call" to call methods you have inherited, or just call them directly. There is a basic search mechanism. Multiple inheritance is not supported. Methods follow the usual Perl semantics. (The first argument is the object, the rest are arguments to the method.)
package ObjectClass; use Carp; use strict; use vars qw($AUTOLOAD); sub call { my $self = shift; my $meth = $self->find_meth(shift); $meth->(@_); } sub def { my $self = shift; { my $meth = shift; my $implement = shift; $self->{meth_cache}->{$meth} = $implement; redo if @_; } } sub find_meth { my $self = shift; my $meth = shift; my $cache = $self->{meth_cache}; if (exists $cache->{$meth}) { return $cache->{$meth}; } elsif (exists $self->{proto}) { return $self->{proto}->find_meth($meth); } else { confess ("Object does not implement method '$meth'"); } } sub new { my $proto = shift; # Note for Merlyn, this time it is not cargo-cult programming! :-P unless (ref($proto)) { my $class = $proto; $proto = { meth_cache => {}, }; bless($proto, $class); } my $self = { meth_cache => {}, proto => $proto }; bless $self, ref($proto); } sub AUTOLOAD { my $self = shift; $AUTOLOAD =~ s/.*:://; return if $AUTOLOAD eq "DESTROY"; $self->call($AUTOLOAD, @_); } package main; # A simple test my $parent = new ObjectClass; $parent->def("hello", sub {print "Hello world\n"}); my $child = $parent->new(); $child->def("goodbye", sub {print "Goodbye\n"}); $parent->hello(); # Calling the defining object $child->hello(); # Inherit the method $child->goodbye(); # Method in the subclass $parent->goodbye(); # Blows up.
Does this make your mock classes easier to implement?

UPDATE
I did this mostly because I thought it would be fun to write. If you want to use this idea, I would suggest looking at Class::Classless or Class::SelfMethods.


In reply to Re (tilly) 1: Nested Classes by tilly
in thread Nested Classes by dcorbin

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    [Corion]: erix: Yeah, I just found that it has no documentation at all on how to circumvent/ eliminate "1+n SELECTs" by building a local hash... I guess I have to make ->has_many do the hash lookup instead of doing the SQL query. But as the problem ...
    [Corion]: ... has only manifested itself so far through the puzzled questions of other bystanders, I won't go deeper at this time. But the DBIx::Class documentation could well do with a document on how to make "it" (that is, ORMs in general) faster ;)
    [Corion]: I find that DBIx::Class, like most ORMs makes things easy until they become performance critical and then makes it horribly hard to change things because the design is highly inflexible if you don't already know about the problems of 1+n :-/
    [choroba]: that's why I don't like similar libraries. They pretend you don't have to learn SQL, but in the end, you have to learn how SQL plus to overcome their own limitations
    [Corion]: "Just write the proper SQL beforehand" is of course the appropriate solution, but if you did that, you wouldn't/couldn't use DBIx::Class either. At least not in an obvious (to me) way.
    choroba scratches a "how"
    [Corion]: choroba: Exactly... But maybe that's just because I'm old and grumpy ;)
    [Corion]: But maybe that could also be a nice talk, how to restructure your DBIx::Class-based app to remove 1+n-style query patterns
    [Corion]: In theory, that should be easy because you should have the "where" clause from part 1 of the patterns and then do the corresponding single select using that where clause to select all rows in one go for the n other parts.
    [Corion]: But in practice I don't see any obvious places documented in DBIx::Class where one would do that and then just feed hash lookups instead of DB lookups for ->has_many results

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