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Subject: Re: [boost] [contract] concepts: pseudo-signatures vs. usage patterns
From: Dave Abrahams (dave_at_[hidden])
Date: 2012-10-13 21:06:43

on Sat Oct 13 2012, Lorenzo Caminiti <> wrote:

> On Sat, Oct 13, 2012 at 2:40 PM, Andrzej Krzemienski <akrzemi1_at_[hidden]> wrote:
>>> > Of course this is achievable only in concepts as language feature. Any
>>> > use-pattern-based concept library will not be able to implement this
>>> > behavior, as far as I am aware.
>>> On the other hand, a pseudo-signature-based library conceivably could.
>> And since this discussion started because Lorenzo wonders which of the two
>> approaches to take for his library, perhaps this limitation gives us the
>> answer.
> ... which is sounding more and more like Lorenzo should leave N3351
> alone, help Matt at least implementing a front-end macros like the
> ones below (s/CONTRACT_CONCEPT/BOOST_GENERIC_CONCEPT or similar), and
> use concepts defined using Boost.Generic in Boost.Contract requires
> clause.

Caveat: I do doubt that you can do the forced conversions in a library
without loss of efficiency, but it's worth a try anyhow.

Dave Abrahams
BoostPro Computing                  Software Development        Training             Clang/LLVM/EDG Compilers  C++  Boost

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