Moose: Importing methods via Traits

morgon has asked for the wisdom of the Perl Monks concerning the following question:

Hi,

I'd like to sweeten some classes with a spoonful of syntactic sugar and wonder if it is possible (and how :-) to achieve the following in Moose:

package Hubba;
use Moose -traits => 'WithBubba';

has a;
has b;

bubba "zappa"; # <- this method should be imported
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So what I want is a trait that implements a method ("bubba") and imports this method into the namespace of every class that uses this trait.

Evidently I could use something like

__PACKAGE__->meta->bubba("zappa");
[download]

But I find that ugly ... is there a nicer way?

Many thanks!

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Re: Moose: Importing methods via Traits by bruno (Friar) on Apr 27, 2009 at 17:56 UTC
You could use a Role: `package DoesBubba; use Moose::Role; sub bubba { ... } 1;` [download] Then in your class: `package Hubba; use Moose; with 'DoesBubba'; # rest of your class here.` [download] The 'bubba' method will be composed into your 'Hubba' class (and any other that consumes this role). Blog	[reply] [d/l] [select]
Re^2: Moose: Importing methods via Traits by morgon (Priest) on Apr 27, 2009 at 21:58 UTC
You could use a Role Ok, maybe I made myself not clear. I do not want a method on the Hubba-class that would be available to it's instances, but I want a method on it that I can call (in the same way as let's say the Moose-supplied method "has" is called) at package-load time to associate a class with a piece of information. As an example think about the name of a database-table where instances of this class will get persisted as in Moose::Cookbook::Meta::Recipe5. My question then is simply is there a way to avoid the uglyness (in my eyes at least) of doing something like " __PACKAGE__->meta->table('User')"	[reply]
Re: Moose: Importing methods via Traits by KSURi (Monk) on Apr 27, 2009 at 19:18 UTC
Also you can use Moose::Exporter to setup methods which will be directly exported to a caller package. As for me, I prefer using Roles as bruno said above.	[reply]
Re^2: Moose: Importing methods via Traits by morgon (Priest) on Apr 28, 2009 at 17:00 UTC
Thanks. Moose::Exporter is exactly what I have been looking for.	[reply]