Re: [Boost-users] [fusion] [range] range::erase vs. fusion::erase

From: mr.chr.schmidt@online.de To: boost-users@lists.boost.org Date: Sat, 17 Sep 2011 09:16:03 +0200 Subject: Re: [Boost-users] [fusion] [range] range::erase vs. fusion::erase

Nathan Ridge writes:

...

Hi,

I have an std::vector<S> and I use boost::erase() from Boost.Range on it.

Now I changed S to be a Fusion sequence type, and as a result, boost::fusion::erase() is being found by ADL and called instead of boost::range::erase().

Which of course gives all kinds of errors because std::vector is not a Fusion sequence.

Is there a way to avoid this, besides qualifying every call to boost::erase() as boost::range::erase()? Basically I want to disable the finding of boost::fusion:: algorithms by ADL.

Thanks, Nate

There is no easy fix. We'd need ADL barriers in fusion, which themselves impose limitations. Have a look at

https://svn.boost.org/trac/boost/ticket/4028

for more information.

The solution I suggested on the Boost-Spirit list was to use SFINAE to disable the boost::fusion:: algorithms for types that are not Fusion sequences. This would solve the issue for many types, but not all (for example, boost::array/std::array is both a Fusion sequence and a range). Nate