Re: [Boost-users] Proto transform using visitor

From: Joel FALCOU (joel.falcou_at_[hidden])
Date: 2008-06-04 16:28:13

Eric Niebler a écrit :
> I'm not sure how the data parameter figures here. Wouldn't the semantic 
> action be conditioned on the expression type? E.g., when an expression 
> is a binary +, do the binary + action. For that, you'd just use a proto 
> grammar decorated with transforms, and not involve the data parameter at 
> all.

Yeah I kinda brainstormed a bit further. What I have now is the 
following. I construct an AST with a simple grammar with no transform.
Then I use a transform that turn the AST into a tuple containing the
pointer to each matrix data int he AST. Then i use another transform to 
compute if the AST is "SIMDizable" aka every terminal is a matrix of the 
same type and this type has a SIMD equivalent. If this is true, then I 
apply another transform that turn all SIMDizable node into their SIMD 
version (basically repalcing proto::tag::plus for ex. into 
my_lib::tag::simd::plus) and evaluates it with a visitor which 
references the data tuples.

> Better IMO to wait until v4 is finished and committed to trunk.
*nods*

> You can certainly write a transform that turns terminal references into 
> values, but that's not the default behavior.
The example is indeed valuable I can see my former error now. Thanks for 
the head up.

-- 
Joel FALCOU
Research Engineer @ Institut d'Electronique Fondamentale
Université PARIS SUD XI
France