Re: [Boost-users] [Boost] [Fusion] Help with tuple adapter

Subject: Re: [Boost-users] [Boost] [Fusion] Help with tuple adapter
From: Joel de Guzman (joel_at_[hidden])
Date: 2010-01-21 20:59:22

On 1/22/2010 7:06 AM, Christopher Schmidt wrote:
> Bill Nell schrieb:
>> I'm having some trouble getting the boost fusion tuple adapter
>> working (the one that makes boost::tuples into conforming sequence
>> types).  I'm assuming that the adapted tuple should now be a legal
>> MPL sequence but mpl::is_sequence yields false and consequently
>> mpl::for_each doesn't work on the tuple type either.  The following
>> program is an illustration of what I am trying to do.  I guess I must
>> be missing something simple?
>
> mpl::for_each should work fine with any built-in or adapted fusion
> sequence. You are experiencing this problem due to fusion not
> specializing mpl::sequence_tag for adapted types. I committed a patch a
> few weeks ago that fixed this problem. Grab a copy of the trunk or the
> release branch and try it again.
> As Joel pointed out, mpl::is_sequence is not required to evaluate to
> mpl::true_ for fusion sequences. Although my patch has the side effect
> that mpl::is_sequence is true for fusion sequences now, you should not
> rely on this behavior. It may not be reproducible with certain
> toolchains and mpl's implementation might change in the future.

Ah yeah, I forgot about that! Thanks as always, Christopher!

Regards,
-- 
Joel de Guzman
http://www.boostpro.com
http://spirit.sf.net
http://www.facebook.com/djowel
Meet me at BoostCon
http://www.boostcon.com/home
http://www.facebook.com/boostcon