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Subject: Re: [boost] [MPL lite or MPL 2] A modest proposal
From: Robert Ramey (ramey_at_[hidden])
Date: 2015-03-05 01:19:22

Eric Niebler-4 wrote
> On 3/4/2015 3:04 PM, Steven Watanabe wrote:
>> I think that building an MPL replacement without sequences would be
>> an exercise in futility. The bulk of my MPL usage is handling MPL
>> sequences.
> Agreed. Also, I don't think the world needs a drop-in replacement for
> the MPL.

I'm not convinced either - but it's better than trying to fix up MPL
using modern C++ to make it easier to maintain.

> The language has changed and so has our thinking. It least,
> it's not clear to me that iterators make sense in a metaprogramming
> environment.

I would agree to that. I would also expect that sequences should
be separate from metafunctions.

I'm not unhappy with leaving MPL as it is. But there have been concerns
that it's hard to maintain and a lot more complicated than it has to be
given the facilities of modern compilers. I also believe that if
were separated, they could eventually be considered for inclusion to the
standard. To my mind, it doesn't make a whole lot of sense to have
type_traits without metafunctions.

Note that I'm suggesting that the MPL be replaced but rather part should
be rebuilt as a new library - maybe it would better to call it meta-function

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