2011/3/20 Vicente Botet <vicente.botet@wanadoo.fr>:
Joachim Faulhaber wrote:
2011/3/20 Vicente Botet <vicente.botet@wanadoo.fr>:
Joachim Faulhaber wrote:
2011/3/19 Frédéric Bron <frederic.bron@m4x.org>:
Maybe the set of functions should be something like
is_callable<plus, LeftOperandType,
RightOperandType>
This is interesting,
yes, I like it
however it would have to be something like:
::boost::is_callable<::boost::type_traits::operators::plus, LHS, RHS>
ideally
boost::is_callable<std::plus, Left, Right>
but std::op_functors seem to be restricted to singly typed functors, which I don't understand,
I don't see op_functors in the standard.
What I mean by "op_functors" are function objects that wrap operators.
20.8 Function objects [1]
e.g. // 20.8.4, arithmetic operations: template <class T> struct plus;
What do you mean by "restricted to singly typed functors"?
And they are template structs parameterized with a single type T instead of e.g.
template <class T, class U=T, class R=T> struct plus;
all three types: Lhs argument type T, rhs argument type U and result type R.
Hi Vicente, there is something nasty about your mail/news reader or the combination of yours and mine. All the less '<' and greater '>' signs (and other special characters) are coming in their html encoding '>' and '<' when they return in your answers. Which is a bit unpleasant. Either the text is unreadable or I have to substitute all of them manually. I use google mail for reading boost list and I have chosen the plain text option, but maybe everyone is using html-encoding now. The phenomenon seems to occur only with *your* replies, but I don't know how others receive the text. As for function objects
20.8 Function objects [1]
e.g. // 20.8.4, arithmetic operations: template <class T> struct plus;
These are part of the old standard as well and their implementation can be found in header <functional>. They are appearing in the new standard unaltered, except for an extension for 3 bitwise operations. // 20.8.7, bitwise operations: template <class T> struct bit_and; template <class T> struct bit_or; template <class T> struct bit_xor; (that should be renamed to bitwise_xxx IMO in order to be more consistent with boost::proto naming.) I see these kinds of functors being used and useful in many contexts and specifically in boost libraries. Also they seem to be reinvented from time to time. They should really be available in their more general form, that is capable of covering all the possible overloads that are possible for the underlying operators. e.g.
template <class T, class U=T, class R=T> struct plus;
but maybe there are specific reasons that forbid such a generalization. I think there shouldn't be any since the more general form contains the old specification as a special case.
Oh, I see.
This extension seems to be not disruptive. Maybe someone could make a proposal
What has to be done for that? Best, Joachim -- Interval Container Library [Boost.Icl] http://www.joachim-faulhaber.de