Re: [Boost-users] [phoenix][lambda] lambda to phoenix translation: get sig (signature) from actor

Subject: Re: [Boost-users] [phoenix][lambda] lambda to phoenix translation: get sig (signature) from actor
From: Joel de Guzman (joel_at_[hidden])
Date: 2010-05-31 03:39:12

On 5/31/2010 11:35 AM, Eric Niebler wrote:
> On 5/30/2010 10:50 PM, alfC wrote:
> <snip>
>> Sure, glad you are interested. Let me know if you need more details,
>> what I am doing now is an experimental code to
>> interface GSL routines from C++ that uses lambda expression.
>> Experimental in the sense that I want to see how far I can get with
>> Phoenix in terms of building a natural (mathematical) language
>> interface to numerical routines.
>> In this experimental code
>> I am trying to make the functions smart enough to recognize *simple*
>> patterns in the expression.
>> In this example, it recognizes the singularity (at 3.) in the integral
>>
>> integral( f( _1 )/(_1 - 3.) , interval(2., 4.));
>>
>> other simple expressions are
>>
>> solve( f(_1) == 2.);
>>
>> just to give you an idea. I am not sure if am repeating someone else's
>> work but when I see expression templates in C++ I see numerical and
>> symbolic mathematics converge into the perfect language to do
>> scientific computing. Of course the patterns do not need to be
>> necessarily *simple* in the future, once we master Phoenix we can go
>> beyond to write transformation rules for expression, in order to do
>> that I must gain complete access to the internal subexpressions and
>> subexpression types.
>
> In that case, I think your best bet is to build your own DSEL using
> Proto. Proto will let you define placeholders and will build expressions
> for you. It will *also* give you the tools to access, analyze and
> transform subexpressions in the ways you describe. In essence, you'll
> need to implement your own mini-Phoenix. That's the bad news.
>
> The good news is: in the (near!) future, Phoenix will be built on top of
> Proto so that you'll be able to use Proto to access, analyze and
> transform Phoenix expressions.
>
> Incidentally, your message is very timely. Joel and I have just been
> discussing off-list the possibilities opened up by giving users access
> to Phoenix expressions at this level. It's really very exciting.

Indeed very timely. See also: http://tinyurl.com/37mguzo
"phoenix domain language (to write mathematical formulas)"

(Cc'ing the author)

This is not the first time Phoenix has been used this way. Yet one of
the reasons why I insist on a simple extension interface. I think we're
on the right track, Eric.

Regards,
-- 
Joel de Guzman
http://www.boostpro.com
http://spirit.sf.net
http://www.facebook.com/djowel
Meet me at BoostCon
http://www.boostcon.com/home
http://www.facebook.com/boostcon