C++ range iterator algorithm to collect result

Asked Feb 05 '14 at 18:04

Active Mar 11 '18 at 08:57

Viewed 311 times

I have written a function to collect the result of a boost iterator range. Here it is:

template<typename Output, typename SinglePassRange>
Output collect(const SinglePassRange & rng)
{
    Output r;
    boost::range::copy(rng, std::inserter(r, boost::begin(r)));
    return r;
}

It is rather convenient:

return collect<std::vector<int>>(ints | filtered(even) | transformed(add1));

This seems like something that really ought to exist already, but I could not find it. (Not to mention it would be nice to "deduce" the return type somehow, which would be a feature more likely found in a standard implementation.)

Does anyone know of a function that behaves like this?

edited Mar 11 '18 at 08:57

nick_g

asked Feb 05 '14 at 18:04

Elliot Cameron

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auto collect(const SinglePassRange& rng) -> decltype(yourList) ? – Floris Velleman Feb 05 '14 at 18:12
Would that translate to `auto collect(const SinglePassRange& rng) -> decltype(Output)`? – Elliot Cameron Feb 05 '14 at 18:18
I think it would translate to: -> decltype(boost::range::range_value::type) – Floris Velleman Feb 05 '14 at 18:26
2

The return type cannot be deduced, because I can ask for whatever type I want as long as I can insert into it. – Matthieu M. Feb 05 '14 at 18:27

C++ range iterator algorithm to collect result

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