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Subject: RE: :decay related question
Date: Wed, 18 Jun 2008 17:28:57 -0600
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Thread-Topic: :decay related question
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From: "Travis Vitek" <Travis.Vitek@roguewave.com>
To: <dev@stdcxx.apache.org>
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=20

>Eric Lemings wrote:
>=20
>Page 490, section 20.3.1.2, paragraph 1 in the latest draft says this:
>=20
>"Let Ui be decay<Ti>::type for each Ti in Types. Then each Vi in VTypes
>is X& if Ui equals reference_wrapper<X>,
>otherwise Vi is Ui."
>=20
>What do you suppose the relationship is between type `X' and types `Ti'
>and `Ui'?  I see how the latter two types are deduced from the=20
>type list
>`Types' but not so sure about how type `X' is deduced from `Types'.

I'm looking at this and I have no idea where VTypes and X are coming
from. Is that an issue, or am I missing something?

That said, I think X is supposed to be Ti. If that were the case then
the definition would make some sense [at least to me].

  Let Ui be decay<Ti>::type for each Ti in Types. Then each
  Vi in VTypes is Ti& if Ui equals reference_wrapper<Ti>,
  otherwise Vi is Ui.

If that is right, then it essentially says that the 'make_tuple'
function transforms reference_wrapper<T> back to T& and for other types
does the normal decay transformation [function to funciton pointer,
array to array pointer, and cv-stripping of all other types].

Travis

>=20
>Brad.
>