Proto for Boost mailing list page: Re: [proto] Visitor Design Pattern

Subject: Re: [proto] Visitor Design Pattern
From: Joel de Guzman (joel_at_[hidden])
Date: 2010-10-22 05:00:56

On 10/22/10 3:15 PM, Eric Niebler wrote:
> On 10/21/2010 7:09 PM, Joel de Guzman wrote:
>> Check out the doc I sent (Annex A). It's really, to my mind,
>> generic languages -- abstraction of rules and templated grammars
>> through metanotions and hyper-rules.
>
> Parameterized rules. Yes, I can understand that much. My understanding
> stops when I try to imagine how to build a parser that recognizes a
> grammar with parameterized rules.
>
>> I have this strong feeling that
>> that's the intent of Thomas and your recent designs. Essentially,
>> making the phoenix language a metanotion in itself that can be
>> extended post-hoc through generic means.
>
> I don't think that's what Thomas and I are doing. vW-grammars change the
> descriptive power of grammars. But we don't need more descriptive
> grammars. Thomas and I aren't changing the grammar of Phoenix at all.
> We're just plugging in different actions. The grammar is unchanged.

And that *is* the essence of it.

Cheers,
-- 
Joel de Guzman
http://www.boostpro.com
http://spirit.sf.net