cross-posted from dams blog

MooseX::Singleton is slow

Just a quick note : if you plan to use MooseX::Singleton, beware ! It is easy to use and it implements properly what it claims, however it is quite slow.

If my profilings are corrects, each call to ->instance() calls meta(), get_metaclass_by_name() one time, and blessed() two times.

So for now I'll avoid it and implement a simplified version using something similar to this :

use Moose;

my $singleton;

sub instance {

    return $singleton //= $CLASS->new();

}

# to protect against people using new() instead of instance()

around 'new' => sub {

    my $orig = shift;

    my $self = shift;

    return $singleton //= $self->$orig(@_);

};

sub initialize {

    defined $singleton

      and croak __PACKAGE__ . ' singleton has already been instanciated'; 

    shift;

    return __PACKAGE__->new(@_);

}

dams.