From: Rozental, Gennadiy (gennadiy.rozental_at_[hidden])
Date: 2004-03-02 12:07:52
> > Actually the point of my remark is that would we be able to
> write meta
> > programs in imperative style instead of FP style
> compilation would be
> > much faster.
> The slowness of metaprogram compilation has almost *nothing*
> to do with the FP style of metaprogramming, and almost
> everything to do with the accidental nature of the
> metaprogram evaluation engine (using template instantiation).
And why do we have so many template to instantiate? Exactly my point:
because we couldn't change type definition we could only create new one. How
many helper templates gets instantiated to remove const types from the
type-list? Should be none. So you are right: it has everything to do with
nature of metaprogram evaluation engine, which is FP based one.
> In fact, you *can* write metaprograms in an imperative
> style, given an appropriate framework designed to interpret
> them correctly. It'll be much slower than what we use today.
You have any grounds for this statement?
> > And Spirit framework would benefit from it the most.
> I doubt that. Parsing in particular has little to gain from
> the use of mutable data.
I meant from compilation time standpoint.
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