[ConceptGCC]|
[ConceptGCC] |
ConceptGCC :Re: newbie question |
From: Karl Meerbergen (karl.meerbergen_at_[hidden])
Date: 2006-11-28 07:01:50
The problem I posted yesterday is solved: I inserted late_check.
Karl
On Mon, 2006-11-27 at 23:34 +0100, Karl Meerbergen wrote:
> Quoting Douglas Gregor <doug.gregor_at_[hidden]>:
> > On Mon, 2006-11-27 at 09:41 +0100, Karl Meerbergen wrote:
> > > I am a new conceptg++ user,
> >
> > Welcome!
> >
> > > Now I want to make a concept
> > >
> > > concept Foo<typename X> {
> > > void X::bar() const ; // works, but not for concepts derived from
> > Foo
> > > } ;
> > >
> > > It is all fine for operators.
> > > Attached is a file that does not compile. Any idea what I am doing
> > > wrong?
> >
> > Your code is correct; this is a bug in the compiler. I have now
> > fixed
> > this bug in the Subversion version of ConceptGCC.
> >
> > Cheers,
> > Doug
> >
>
> I see. Thanks for your prompt reply! I have another strange behaviour
> which I am unable to develop a small test program for. I can describe it
> as follows.
>
> I have a templated function, with a where clause to put conditions on
> the templated arguments, which works fine.
> When I make it a functor, it does not work. I include a piece of code to
> give you an idea, but as I said, I cannot generate a simple example.
>
> The following piece of code (the function foo_function()) is ok.
>
> template <DenseVectorCollection C, VectorExpression E>
> where std::Assignable< typename C::dereference_type, typename
> E::const_dereference_type >
> && std::Integral< typename C::size_type >
> && std::SameType< typename C::size_type, typename E::size_type >
> void foo_function( C& c, E const& e ) {
> typedef typename VectorExpression<E>::size_type size_type ;
> assert( c.size() == e.size() ) ;
> size_type size = e.size() ;
> for (size_type i = 0 ; i < size ; ++i ) c(i) = e(i) ;
> }
>
> But then the functor version struct foo:
>
> template <DenseVectorCollection C, VectorExpression E>
> where std::Assignable< typename C::dereference_type, typename
> E::const_dereference_type >
> && std::Integral< typename C::size_type >
> && std::SameType< typename C::size_type, typename E::size_type >
> struct foo {
> void operator() ( C& c, E const& e ) const {
> typedef typename VectorExpression<E>::size_type size_type ;
> assert( c.size() == e.size() ) ;
> size_type size = e.size() ;
> for (size_type i = 0 ; i < size ; ++i ) c(i) = e(i) ;
> }
> };
>
> This produces the error message
>
> vector.cpp: In member function ‘void glas::foo<C, E>::operator()(C&,
> const E&) const’:
> vector.cpp:25: error: no match for ‘operator==’ in ‘c->C::size() ==
> e->E::size()’
> /usr/local/conceptgcc/4.1.1/lib/gcc/i686-pc-linux-gnu/4.1.1/../../../../include/c++/4.1.1/bits/concepts.h:155:
> note: candidates are: bool std::Integral<typename
> glas::VectorExpression<C>::size_type>::operator==(const typename
> glas::VectorExpression<C>::size_type&, const typename
> glas::VectorExpression<C>::size_type&)
> vector.cpp:26: error: ‘size_type’ has no copy constructor
> vector.cpp:27: error: conversion from ‘int’ to non-scalar type
> ‘size_type’ requested
> vector.cpp:27: error: no match for ‘operator<’ in ‘i < size’
>
> I have the impression that the where clause is not transferred to the
> member function of the functor. Does ring a bell?
>
> Karl
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-- Karl Meerbergen Katholieke Universiteit Leuven Department of Computer Science E-mail: karl.meerbergen_at_[hidden] URL : http://www.cs.kuleuven.be/cwis/research/nalag/ Phone : +32 16 327700 (secretary) Fax : +32 16 327996