On Sun, Mar 30, 2008 at 11:18 PM, shunsuke <pstade.mb@gmail.com> wrote:
Giovanni Piero Deretta wrote:
OTOH, refactoring a lambda on a separate function object is a pain if you have to figure out the result of a complex composition of polymorphic function objects (result_of helps only to a point). For example, what is the result of:
filter_view(reverse_view(mapped_view(range, op)), filter)
(I often find much more complex expressions in my code).
BTW, how about this: http://tinyurl.com/23jdk6 return_of is a simple wrapper around result_of.
Ah, yes, basically recursive evaluation of result_of. I have it in my bag of tools (and as an added benefit, is boost::lambda, compatible, but I guess return_of is too); it still bothers me to have to write an expression two times, one to deduce the result_type and one to actually compute the value. And it seems that things won't improve much with decltype [1]. This is in fact the reason for my compose<> template idea: If you can't avoid writing a type expression, you might as well just write that. [1] it would be great if we also had the automatic one-line-lambda result type deduction in normal functions (and polymorphic lambdas too, but that's another story :( ). -- gpd