Just an addition to the second question... Unfortunately, I forgot my MPL book at work :( But I remember, that in the chapter about physical quantities authors show how to compare quantity types (one which is iniaital mpl::vector like mpl::vector_c<int, 0, 1, 0, ...> and the other an instance of mpl::vector which is produced as a result of function application (which logically also results in the same template arguments but have different type)) this chapter might help you. With Kind Regards, Ovanes. -----Original Message----- From: Ovanes Markarian [mailto:om_boost@keywallet.com] Sent: Freitag, 16. März 2007 21:44 To: boost-users@lists.boost.org Subject: Re: [Boost-users] [MPL] 2 Newbie Questions BOOST_MPL_ASSERT operates on types, this also applies to mpl::or_ Try out: #include <boost/mpl/bool.hpp> #include <boost/mpl/assert.hpp> #include <boost/mpl/or.hpp> BOOST_MPL_ASSERT((true_)); //true is not a bool value it is a type it has underscore... BOOST_MPL_ASSERT(( mpl::or_(false_, boost::is_same<CallerConstraints, CodeConstraints::Ignore_Constraints>) )); //false_ also a type... With Kind Regards, Ovanes -----Original Message----- From: Scott Meyers [mailto:usenet@aristeia.com] Sent: Freitag, 16. März 2007 20:38 To: boost-users@lists.boost.org Subject: [Boost-users] [MPL] 2 Newbie Questions I'm trying to use the MPL for the first time, and I have two questions. First, I want to use BOOST_MPL_ASSERT to say that at least one of two conditions is true. For the time being, one of the conditions is always false, so this is what I've tried: BOOST_MPL_ASSERT(( false || boost::is_same<CallerConstraints, CodeConstraints::Ignore_Constraints> )); It won't compile, so I tried this: BOOST_MPL_ASSERT(( mpl::or_(false, boost::is_same<CallerConstraints, CodeConstraints::Ignore_Constraints>) )); It won't compile either. I'm guessing that I have to use mpl::false_ or something in place of false, but that doesn't work either. Can somebody please tell me the proper way to say what I want to say? My second question is about the existence of an MPL algorithm akin to the STL algorithm includes. Given two MPL vectors V1 and V2, I want to know if all the types in V1 are also in V2. I know about mpl::contains, but I can't find mpl::includes. Is there one, or do I need to write it myself? I have the MPL book, so references to that are fine, in addition to anything online. Thanks, Scott _______________________________________________ Boost-users mailing list Boost-users@lists.boost.org http://lists.boost.org/mailman/listinfo.cgi/boost-users _______________________________________________ Boost-users mailing list Boost-users@lists.boost.org http://lists.boost.org/mailman/listinfo.cgi/boost-users