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Subject: Re: [boost] [Review] Type Traits Extension by Frederic Bron - Review summary and decision
From: Stewart, Robert (Robert.Stewart_at_[hidden])
Date: 2011-04-25 07:53:25

Jeffrey Lee Hellrung, Jr. wrote:
> On Thu, Apr 21, 2011 at 12:13 PM, Stewart, Robert
> <Robert.Stewart_at_[hidden]>wrote:
> > Jeffrey Lee Hellrung, Jr. wrote:
> > > Also, while we're on the topic of what *I* prefer: I still
> > > prefer "has_xxx". To me, it has an implicit association
> > > (to me, anyway) to the names of trait predicates; it has
> > > simplicity and brevity; and it has existing use in
> > > Boost.TypeTraits.
> >
> > What about all of the "is_" prefixed traits
> Those, too!

OK, so there are names in TypeTraits with both "has_" and "is_," so "has_" isn't the only prefix you should associate with the library. That was my point.

> > and other names in Boost.TypeTraits with prefixes like "add_"
> > and "remove_,"
> Those aren't predicates...
> > and those without a prefix?
> Such as...?

I was thinking of "existing use in Boost.TypeTraits" while forgetting "implicit association to the names of traits predicates" in what you wrote.

> > There's clear precedent for different prefixes for different
> > purposes within the library. Remember that "has_" implies
> > ownership or inherent characteristic which doesn't apply to a
> > namespace scope operator.
> Well, I don't think it's confusing to say that "A has a plus
> operator" is equivalent to "A + A is well-formed". Like I said,
> I understand that arguments against "has_xxx", but it's still
> more natural to me than "can_call_xxx".

That's a valid point in that case. However, don't forget that it can also be A + B, in which case the operator bridges two types and is, therefore, part of neither interface or else somehow part of both. "has_" doesn't work as nicely then.

Rob Stewart robert.stewart_at_[hidden]
Software Engineer using std::disclaimer;
Dev Tools & Components
Susquehanna International Group, LLP

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