[boost] Re: tuple patch (constructing from a pair)

From: Larry Evans (cppljevans_at_[hidden])
Date: 2005-02-15 10:30:21

On 02/15/2005 08:08 AM, Larry Evans wrote:
[snip]
>> Yes, it is a non-member function. No, it does not mutate s.
>> It does return another set. It is purely functional (no side-
>> effects).
Then it's different from tuple<T1,...,Tn> since any mutating
operation Ti::op on an instance of Ti can be performed on the
corresponding member variable in an instance of tuple<T1,...,Tn>?

See boost-sandbox.sourceforge.net/vault/cppljevans/field_visitor_tests
/field_sets.hpp for an example of what I had thought you were
talking about here:

 > fusion::vector, fusion::list, fusion::set and fusion::map
 > all have data. These are different incarnations of the
 > tuple with different characteristics.

when you said fusion::set had data.  Having data implies, at least
to me, that the data can be modified.