From: Daniel Berger <djberg96@...>
Date: 2006-06-15T00:24:08+09:00
Subject: Re: Cut-based AOP

Austin Ziegler wrote:
> On 6/14/06, Ruby Newbie <rubynewbie@gmail.com> wrote:
>> Looking around, you have hundreds of posts, and you're involved as a
>> mentor in Google Summer of Code "Automated Wrapper Generation for
>> Information Extraction" arena. I take it you have the experience to
>> back up what you're saying.
> 
> I like to think I do, at least. I will freely admit that I don't "get"
> AOP. I *understand* the reasons for AOP (adding logging for something
> you no longer necessarily have source access to, for example), but I
> have *long* felt that AOP is a pure hack.
> 
>> Can you provide references to better and more-established ways of
>> offering such extensibility?  I looked briefly at traits which you'd
>> alluded to earlier, but it requires changes to the core code for
>> trait/hook insertion.  I'm interested to read about other mechanisms
>> which are more maintainable and extensible than AOP in Ruby if you
>> could please share them.
> 
> If you control the source, write the source better. If you *want*
> extensibility points, provide clear hooks.
> 
>  class Foo
>    def bar
>      pre_baz if respond_to? :pre_baz
>      baz
>      post_baz if respond_to? :post_baz
>    end
>  end
> 
> Matz will be providing (somewhat) cleaner ways to do this, but that's
> the essential nature of the beast. It's a form of plugin-style
> programming and that's well understood, while AOP is a poorly defined
> and easily misunderstood beast.
> 
> Similarly, mixins provide the main capability that Ruby needs -- but the
> original programmer has to write the code to be able to deal with this
> properly. And if they don't, you can always inherit or compose.
> 
> I think that it's important to note that *even now* (five years on from
> the PARC research) you can't find many clearly-written, concise
> explanations of AOP and why you'd want it. It's all buzzwords.
> 
> AOP may be valuable. But I have yet to see anything that convinces me
> that it's worth all the bother. It's sort of like Inversion of Control.
> Interesting, but not relevant to most (98%+) needs.
> 
> -austin

What about taking this concept and applying it to the great Unicode debate?

# Pseudocode
class String
    def pre
       self.replace(MultiToWide(self)) if TextIsUnicode(self)
    end
end

Maybe smarter minds than I could take this idea further.

Regards,

Dan