Re: Templated Lambda Functions?

From:
SG <s.gesemann@gmail.com>
Newsgroups:
comp.lang.c++.moderated
Date:
Wed, 30 Mar 2011 16:40:15 CST
Message-ID:
<46a45b24-1fdc-4e31-b039-e7a01cd85e06@r6g2000vbo.googlegroups.com>
On 30 Mrz., 04:51, Andy Champ wrote:

[subject: templated lambda functions?]
They're not allowed are they? Any ideas why not?


If you mean lambdas with templated function call operator: no, they
don't exist. They are mentioned here and there as "polymorphic
lambdas" in C++0x discussions (as opposed to "monomorphic lambdas" we
already got). But I did not see any proposal for polymorphic lambdas.
At least I cannot recall having read proposals of this kind.

I have a function that takes the ends of a set, in the form of a pair of
iterators, and picks items out until it is happy - something like

void Func(const SomeIteratorType & first, const SomeIteratorType & last)
{
   SomeIteratorType iter;
   bool notdone = true;
   for (iter = first; iter != last && notdone; ++iter)
   {
     // some processing
   }
}

I'd like to be able to pass sometimes a forward iterator, and sometimes
a backwards one, and write it as a lambda so it has access to the other
local variables. I've ended up with a templated free function with
half-a-dozen parameters :(


Unfortunately, I don't understand your problem. What is "it" in "and
write it as a lambda"?

SG

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