Re: [Boost-users] [Proto] proto::reverse_fold_tree

Subject: Re: [Boost-users] [Proto] proto::reverse_fold_tree
From: Eric Niebler (eric_at_[hidden])
Date: 2009-02-02 14:38:35

Joel Falcou wrote:
> Dave Jenkins a écrit :
>> You can see that both are broken if you try the expression 
>> "(a*b+c)*(do*e+f)".
>> That displays [f e d] for reverse_fold_tree and [a b] for fold_tree.
>>
> Then, is there anyway to implement a real Depth First or Breadth First 
> traversal of the whole AST in Proto ?

Certainly, but not with any of Proto's "built-in" transforms. Generic 
tree traversal is a HUGE domain, and not something I can just whip out. 
;-) Dan Marsden has been working on that problem for some time with his 
Boost.Traversal library. The Haskell folks have done lots of work in 
this area, too. Just Google "Scrap Your Boilerplate" and see how deep 
the rabbit hole goes.

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