[ConceptGCC]|
[ConceptGCC] |
ConceptGCC :variadic templates and concepts |
From: Sylvain Pion (Sylvain.Pion_at_[hidden])
Date: 2007-11-19 13:42:31
Dear all,
I am working on specifying an extension of std::min() to a variable
number of arguments using variadic templates. For the concept-enabled
version, I need to define a concept that constrains all arguments
to be of the same type. That is, an extension of std::SameType to the
variadic case.
I am stuck with a problem using conceptgcc, which I fear is a bug,
or maybe a misunderstanding on my side. A reduced test-case is below,
which generates the following error message:
bug_report.cpp: In function 'const T& f(const T&, const T&, const Args&
...)':
bug_report.cpp:23: error: no matching function for call to 'f(const T&,
#'type_pack_expansion' not supported by
dump_type_prefix#<typeprefixerror>&#'type_pack_expansion' not supported
by dump_type_suffix#)'
------------------------------
concept SameType <typename T, typename... Args> {}
template <typename T>
concept_map SameType<T> {}
template <typename T>
concept_map SameType<T, T> {}
template <typename T, typename... Args>
requires SameType<T, Args...>
concept_map SameType<T, T, Args...> {}
template <typename T>
const T&
f(const T&a)
{ return a; }
template <typename T, typename... Args>
requires SameType<T, Args...>
const T&
f(const T&a, const T&b, const Args&... args)
{ return f(a, args...); }
------------------------------
Is there any way to fix this?
-- Sylvain Pion INRIA Sophia-Antipolis Geometrica Project-Team CGAL, http://cgal.org/