Re: [Boost-users] [Tuple] augment_tuple, patch, or whatever... maybe MPL?

Subject: Re: [Boost-users] [Tuple] augment_tuple, patch, or whatever... maybe MPL?
From: Robert Jones (robertgbjones_at_[hidden])
Date: 2010-11-23 08:21:47

On Tue, Nov 23, 2010 at 12:05 PM, Hossein Haeri <powerprogman_at_[hidden]>wrote:

> Dear all,
>
> Is there any function in Boost.Tuple which works like this for n-tuples for
> any given n?
>
> template<typename T1, typename T2, typename T3>
> tuples::tuple<T1, T2, T3> augment_tuple(tuples::tuple<T1, T2> tup, T3 t3)
> {
>  return tuples::make_tuple(tup.get<0>(), tup.get<1>(), t3);
> }
>
> (Obviously, here n == 2.) The purpose of this augment_tuple (or, patch, or
> whatever) is to take an n-tuple and a new element and patch the new element
> to the end of the n-tuple in order to get a (n + 1)-tuple. Repetitive code
> which can produce enough overloads for a large enough n is of course
> trivial. I'm wondering whether MPL has a utility which can automated this
> though?
>
>
I think this is what you need. Since Boost.Tuple can be a conforming
ForwardSequence (with the appropriate header),
this does exactly what you want.

http://www.boost.org/doc/libs/1_43_0/libs/fusion/doc/html/fusion/algorithm/transformation/functions/push_back.html

- Rob.