Brad Austin writes:

The MPL Reference Manual page for at_c:

http://www.boost.org/libs/mpl/doc/refmanual/at-c.html

Contains the following sample code:

typedef range_c<long,10,50> range; BOOST_MPL_ASSERT_RELATION( (at_c< range,0 >::value), ==, 10 ); BOOST_MPL_ASSERT_RELATION( (at_c< range,10 >::value), ==, 20 ); BOOST_MPL_ASSERT_RELATION( (at_c< range,40 >::value), ==, 50 );

Does at_c<unspecified>::value exist?

Nope, the above should be BOOST_MPL_ASSERT_RELATION( (at_c< range,0 >::type::value), ==, 10 ); BOOST_MPL_ASSERT_RELATION( (at_c< range,10 >::type::value), ==, 20 ); BOOST_MPL_ASSERT_RELATION( (at_c< range,40 >::type::value), ==, 50 ); ^^^^^^ Fixed in the CVS, thanks for the report! -- Aleksey Gurtovoy MetaCommunications Engineering