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From: Joel de Guzman (joel_at_[hidden])
Date: 2006-05-12 01:58:29

Tobias Schwinger wrote:

> 2. Fusion and MPL placeholder expressions
> MPL placeholder expressions are very convenient for specifying the result
> because of their lazy nature (see lines 267, 312). Of course, this approach
> trades compile time for syntactic sugar. The syntactic sugar might not be
> entirely irrelevant, because it allows us to emphasize even complex problems
> with little code.


> So, I still wonder, whether it is a good idea to use MPL lambda for the
> result computation or not. Is it?

I think so, yes.

> If so (even occasionanlly), it would be necessary to have at least accessors
> for pair members (they are needed to keep the evaluation lazy, see line 211)
> or, ideally, if there would be a normalization between the STL and the MPL
> pair concepts (then MPL's accessors, 'first' and 'second', could be borrowed).

If my suggestion to make mpl/fusion pair fully conforming mpl/fusion
sequences is accepted, then you can use code like mpl::begin<_> or
mpl::at<_, N>.

> (It would also be cool if one could just typedef the lambda expression to nested
> result or inherit from a wrapper. I don't know whether it's possible and a good
> idea - this part is just loud thinking)...

Hmmm... can you elaborate. I lost you here.


Joel de Guzman

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