[boost] Re: is_convertible: rationale and wording

From: Gennaro Prota (gennaro_prota_at_[hidden])
Date: 2003-01-28 07:34:14

On Tue, 28 Jan 2003 12:03:54 -0000, "John Maddock"
<john_maddock_at_[hidden]> wrote:

>Following the recent is_convertible discussion, I've put the following
>together:
>
>Rationale:
>~~~~~~
>
>There has been some fairly intense discussion on boost mailing list about
>the is_convertible template, one suggestion was that since only expressions
>(and not types) are convertible to a type or not, that is_convertible should
>be an intrinsic binary operator whose first argument was an expression, and
>whose second was a type.

Another idea was to use *function* templates, instead of a class
template because that would allow access checking in the calling
context. Since in that case you have to use an expression, then the
question is:

is there, among the uses of is_convertible that you have listed, any
usage where no expression could be used (so that you would need to see
if the "type" is convertible)?

I'm sorry to ask this to you instead of looking myself, but I don't
have time right now to examine all the uses you mentioned. OTOH, since
you have, to say, already scrutinized them that should be quick and
easy to answer for you.

Genny.