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. -Christopher