Re: [boost] [Review] Type Traits Extension ending tomorrow

Subject: Re: [boost] [Review] Type Traits Extension ending tomorrow
From: Stewart, Robert (Robert.Stewart_at_[hidden])
Date: 2011-03-18 12:51:19

John Maddock wrote:
>
> >(1) has_operator_xxx seems to be imprecise and misleading.
>
> How so?  Personally I like the idea of a common prefix for
> all of these.

The intention is that "has_operator_xxx" be read as "expressions involving these two types can use operator xxx."  The types needn't "have" such an operator where "have" suggests membership, that the operator is a member of a type.

A common prefix doesn't have to be common for all type traits.  There are already "add_," "has_," "is_," "make_," and "remove_" common prefixes.  Note also that those beginning with "has_" refer to properties of types.  These new traits do not.

> >(2) has_operator_xxx introduces a redundant prefix
> > 'has_operator' that IMO is unnecessary
>
> Maybe, but it makes it explicit what you're testing, and puts
> all the operator traits together in the alphabetical index -
> a small point I know, but it is useful none the less!

That's actually a good argument against using "has_" because you *don't* want these new traits grouped with the existing "has_" traits.

> >(3) If there are close relationships between Concepts and operator
> >traits their names should express this relation as well.
> >
> >My current proposal is:
> >
> >plus_assign_callable or even better
> >plus_assingable   instead of  has_operator_plus_assign
>
> I'd prefer is_plus_assignable if we go that route.

is_add_assignable

(The operation is addition followed by assignment, not plus followed by assignment.)

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

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