Re: Front-end

on Sat Jun 30 2007, John Moeller <fishcorn-AT-gmail.com> wrote:

> Daniel Wallin wrote:
>> John Moeller wrote:
>>> I was wondering about the front-end a little bit, and since it would be 
>>> essentially a DSEL, has any thought been given toward using Proto for 
>>> the Langbinding front-end?
>> 
>> I don't know which DSEL you're thinking of. 
>
> The class_<>, def(), etc.  It's a DSEL that describes a class.
>
>> IIRC we use type erasure
>> everywhere, in which case proto won't help. 
>
> Type erasure.  That's the term I was looking for, thank you.  :)
>
> There's only type erasure (AFAICT) at the point where xxx binds.  Tuple 
> transformations and other compile-time operations are used internally in 
> langbinding.  All I'm saying is that it may be useful.  If you don't 
> think so, so be it.

It would be useful if we needed to statically generate
language-specific bindings from the user's binding code.  However,
it's our hope to avoid that.

> Additionally, I've been wondering if type erasure is strictly necessary 
> anyway.  A while back, you and Dave had discussed a system where static 
> type information was utilized.  

Static type information will always be "utilized."

> It seems that the idea of static converter generators was abandoned
> in favor of type erasure, but I wasn't able to discern why.  

It enables us to have a single compiled front-end language binding
that can be used with any number of backend languages.

> That's the point that I was trying to get at in my other post.  I
> wanted to revisit the issue, if possible.

I don't think it's possible to get any advantage out of keeping more
static information around... but I still have to get to your other
posts ;-)

>> We might have some parts
>> that doesn't use type erasure, like the policy specification syntax, but
>>  I don't think we'd want to do any tree transformations on that anyway..
>
> Policy specification syntax?  Are you referring to something in 
> Boost.Python or in Luabind?

Something proposed for Langbinding.

-- 
Dave Abrahams
Boost Consulting
http://www.boost-consulting.com

The Astoria Seminar ==> http://www.astoriaseminar.com


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