From: Michel Demazure <michel@...>
Date: 2011-02-14T00:26:03+09:00
Subject: Re: DCI and ruby

Andrew Wagner wrote in post #981397:
> Hm, interesting question. Can you give an example of when you might need
> to
> un-assign a role? It only lasts for the length of the request anyway, if
> I
> understand correctly.

I was thinking in general terms, not in a Rails setting. Just thinking 
about how the DCI idea could be useful in my work, as it seems very 
ruby-esque (duck typing > classing).

I can imagine cases where the given class has a given instance method, 
say :foo. The object is assigned a role where the :foo method is 
redefined. Then you assign a new role, which uses the generic :foo 
method and you want it back.

If you use mix/unmix, then when you assign (= mix) a role, you have to 
know if you have an already mixed-in role to unmix and which one. You 
need to distinguish two types of mixins, permanent and temporary. Just a 
small addition to the mechanism indeed, unless you want to mix (!) 
things (including/excluding in roles or vice versa). Difficult to say 
more without real examples.

Has this question something to do with the 'refinement' proposal ?

_md

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