This may be a little OT but as it applies to metaprogramming and ideas from the book I thought it the best place to ask. On pgs 191/2 of the MPL book (section 9.5) is a set of ideas meant to introduce the inherit_linearly metafunction. There are some things I want to do that suggested this was actually the better way to go for me. So I implemented something like the following: struct empty {}; template < typename FIELD, typename CDR > struct rec : CDR { typename FIELD::type value; rec() : value() {} }; template < typename VEC > struct generate_record //: boost::mpl::inherit_linearly< VEC, boost::mpl::inherit< rec<pl::_2>, pl::_1> >::type : boost::mpl::fold< VEC, empty, rec< pl::_2, pl::_1> > {}; I implemented a getter function like so: template < typename FIELD, typename CDR > typename FIELD::type & get(rec< FIELD, CDR > & r) { return r.value; } Now, minus the "field" concept this seems to be exactly the same basic thing. The field concept is something I need for what I'm working on that currently, for this test, just has a type in it. I create a "record" like so: typedef generate_record< boost::mpl::vector<field1, field2, field3>
::type test_record;
When I print the type I end up with: "rec<field3,rec<field2,rec<field1,empty> > >" and in main attempt to access it: test_record tr; get<field1>(tr) = 3; This works fine in comeau and I'd expect it to work anywhere but MSVC++ 8 doesn't like it. It says that the FIELD param is ambiguous and could be field1 (what I specified in the call) or field3 (the first field on the inheritance tree). The error text is exactly: 1>e:\dev_workspace\experimental\record_generation\record_generation\main.cpp(78) : error C2782: 'FIELD::type &get(rec<FIELD,CDR> &)' : template parameter 'FIELD' is ambiguous 1> e:\dev_workspace\experimental\record_generation\record_generation\main.cpp(58) : see declaration of 'get' 1> could be 'field3' 1> or 'field1' I'm calling this a compiler bug at this point. I suspect many here have had to deal with this, since it's basic template usage, and might know a workaround. Or maybe you see something I've done incorrectly.