I'm now playing with the new sub-domain compatibility mode and I got some error. The code here is what I am actually compiling: http://codepad.org/lDUYCVHY Line 11 should have worked as I understood the subdomain thing but it bails out as : /usr/local/include/boost-trunk/boost/proto/detail/as_expr.hpp:203: error: conversion from ‘const nt2::containers::expr<nt2::containers::vector<int>, nt2::containers::table_tag, boost::proto::tag::terminal, boost::proto::exprns_::is_proto_expr>’ to non-scalar type ‘nt2::containers::expr<nt2::containers::expr<boost::proto::exprns_::expr<boost::proto::tag::terminal, boost::proto::term<std::vector<int, std::allocator<int> > >, 0l>, nt2::containers::vector_tag, boost::proto::tag::terminal, boost::proto::exprns_::is_proto_expr>, nt2::containers::table_tag, boost::proto::tag::terminal, boost::proto::exprns_::is_proto_expr>’ requested Did I miss a point in the domain/sub-domain relationship and hwo to use it or is it a bug ? Thanks in advance