On Friday, 29 March 2013 at 07:52:13 UTC, deadalnix wrote:
That sound unimplementable, sorry.
Plus, to me it seems like the same thing they're proposing to
implement in C++. This is a quote from the concepts-lite proposal
paper http://isocpp.org/files/papers/n3580.pdf page 17:
For example, we define Totally_ordered like this:
template<typename T>
constexpr bool Totally_ordered()
{
return Weakly_ordered<T>() && Equality_comparable<T>();
}
The relationship between the requirements of Totally_ordered and
Equality_comparable can be pictured like this: [..]
Totally_ordered subsumes Equality_comparable because its
requirements include those of the latter. This relation holds for
any constraint predicate that explicitly includes another.
It is often the case the case that constraints overlap, with
neither subsuming the other. For example, this is true of the
Container and Range concepts described in the previous section.
[..]
The subsumes relation is used to determine which of two templates
is more constrained. In particular, a template T is more
specialized than another, U iff they have the same generic type
and the requirements of T subsume those of U. This relation is
used to different templates with the same type when computing
which is more specialized. Note that a constrained template is
always more specialized than an unconstrained template.
