Re: [Boost-users] [Proto] automaitcally convert class to proto literal

Subject: Re: [Boost-users] [Proto] automaitcally convert class to proto literal
From: Eric Niebler (eric_at_[hidden])
Date: 2009-01-05 11:47:57

Daniel Oberhoff wrote:
>> Daniel Oberhoff a écrit :
>>> I might have gotten the terms wrong. But the way I got it working
>>> now is with using proto::lit which turns things into literals. I
>>> tried subclassing terminal with my array class, but that way the
>>> tree did not keep a reference to the array, and thus could not
>>> be evaluated as such.
>> 
>> Just make a array_data class that contains your data and make your
>> user level array class extends terminal<array_data>::type. The
>> vec3 example in the doc is exacly this and I used variations of
>> this for like 4 or 5 array like DSEL since proto is available.

Right.

> Ok, I looked into that. Works better than my previous approaches. 
> Though I would like it much better if I don't have to split my class 
> into an internal data class and a user interface, since I would like 
> to use the whole interface in the proto evaluators.

Can you give me an example of where this complicates your implementation?

> Also, since the extends mechanism makes the data class end up a
> member of the derived class it is hard to access the derived class
> from the base class. Is this fundamentally impossible?

I don't know. What are "base" and "derived" referring to in the above
paragraph?

-- 
Eric Niebler
BoostPro Computing
http://www.boostpro.com