Re: [boost] [Review] Formal Review of Proposed Boost.Ratio Library

Subject: Re: [boost] [Review] Formal Review of Proposed Boost.Ratio Library
From: Stewart, Robert (Robert.Stewart_at_[hidden])
Date: 2010-10-07 09:32:20

Howard Hinnant wrote:
> >> From: "Stewart, Robert" <Robert.Stewart_at_[hidden]>
> >>
> >>> The use of enable_if to control the contexts in which the
> >>> copy constructor and copy assignment operator apply goes
> >>> beyond the standard's specification.  That means boost::ratio
> >>> behaves differently than will std::ratio.  I think this will
> >>> lead to surprising results when one transitions from one to
> >>> the other.
[snip]
> I would be tempted to consider this extension to the standard
> semantics based on its technical merits alone, motivated by
> Beman's more general policy statement:
>
> On Oct 2, 2010, at 8:11 AM, Beman Dawes wrote:
>
> > One of the advantages of Boost is that we can add extensions and get
> > user experience before something gets standardized. That's very
> > helpful to the C++ committee.

That's a fine approach, but it should be treated as an extension: the user should have to enable it.  That avoids surprises when migrating to std::ratio (as it is defined presently).

_____
Rob Stewart                           robert.stewart_at_[hidden]
Software Engineer, Core Software      using std::disclaimer;
Susquehanna International Group, LLP  http://www.sig.com

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