Re: [Boost-users] [tuple] How to manipulate the types

From: Joaquín Mª López Muñoz (joaquin_at_[hidden])
Date: 2006-05-29 11:41:01

Adrián Etchevarne ha escrito:

> Problem:
>   How can I get a tuple type from a tuples::cons<> list ?
> example:
>   given the type:
>      cons<int, cons<float, cons<int, null_type> > >
>
>   obtain
>      tuple<int, float, int>
>
> Real problem:
>    I need to insert a type T at the beginning of a tuple, how I can do this?
>
> example
>    given the type T and  tuple<int, float>, obtain a tuple<T, int, float>
>
> Thanks in advance,
>         Adrián

Hi Adrián, I think you've got to resort to brute force, although
Boost.PP helps a lot with this kind of tasks. Please find attached
a possible implementation of a tuple_from_cons helper metafunction,
though I'm sure the PP experts out there could come out with simpler
and nicer formulations.

Joaquín M López Muñoz
Telefónica, Investigación y Desarrollo

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