From: Trans <transfire@...>
Date: 2007-10-24T20:05:28+09:00
Subject: Re: Ruby-Traits 0.2 released (sorry long)



On Oct 23, 4:16 pm, "Robert Dober" <robert.do...@gmail.com> wrote:
> Hi list
>
> after some very interesting input I decided to rewrite Ruby-Traits completely.
>
> http://rubyforge.org/frs/?group_id=4642&release_id=15737
>
> I have decided to implement two different kinds of traits:
> * ruby-traits
> and
> * pure-traits.
>
> In detail:
> * ruby-traits are mimicking some of the properties of traits but violate the
> flattening property. They implement some of the more dynamic features
> of modules and are in fact module based. The code is heavily influenced
> by Thomas Sawyer's traits from Facets. Many thanks to Thomas for the
> permission to use his code. Note that Thomas' traits of Facets is yet another
> different beast.
>
> * pure-traits implement traits in the strict sense of their definition
> here:http://portal.acm.org/ft_gateway.cfm?id=1028771&type=pdf&coll=GUIDE&d...
>
> They obey the flattening property, using a trait is exactly as defining
> its methods inline, no modules are used and inheritance is unchanged.
> All trait combination rules are obeyed (associative, communative, e.g.)
>
> The main purpose of pure-traits is to play around with them and to see the
> benefits and shortcomings of traits based design.
>
> The syntax has changed, again inspired by Factes, trait aliasing is done
> via #* now, thus traits aliased and combined can be expressed more
> naturally:
>   t1 * { :t1_a => :a } + t2 * { :t2_a => :a }
> works now as expected.
>
> In addition to the traditional trait operations +, - and *, I have
> implemented & to allow of selective usage of methods.
> I believe that the usage of this is normally a bad sign for the design
> but sometimes it might be a handy feature.

[snip]

Whew! Yep, long, but interesting. I'll have to check the ruby-traits
code and see if there's any cross-pollination to be had. Seems like
maybe the main difference between this and Facets is the use of the
Traits < Module class (where as Facets just extends Module). I'm also
curious about the & method.

Great work!

T.