On Fri, Oct 15, 2010 at 1:23 AM, joel falcou
<joel.falcou@lri.fr> wrote:
On 15/10/10 09:22, Eric Niebler wrote:
Goodness Joel, I have no idea what you're asking. What's the "visitor
level"? Why would you have to transform the AST? What are you trying to
do, exactly?
I have some AST that represent arithmetic computation.
I know that when I encouter a "a + b*c" node (where a,b,c can be expression
themselves), I can evaluate it using an optimised call instead
of chaining + and *.
Currently I do this by transforming my AST into another where a+b*c
is replaced by madd(a,b,c). Now, with your specialization of dispatch using
grammar instead of tag, I can check for a+b*c and dispacth to a special trasnform
instead of having a bloated trasnform next to that.
Joel, I think I still must be missing something. You also have an extensible grammar w/ pluggable transforms, is that right? Then if I understand your requirements, then I think the answer is yes, you can dispatch to the appropriate transform based on the grammar for "a+b*c". But it's hard to say without knowing a little more.
Eric