is_container itself should be MPL boolean instead of type typedef.

[Yasutaka ATARASHI <atara-y@…>]

Expression Semantics in http://www.boost.org/doc/libs/1_46_1/libs/spirit/doc/html/spirit/advanced/customize/is_container.html says that is_container<C>::type is MPL Boolean Constant.

However, at least, inside boost/spirit/home/qi/detail/pass_container.hpp and boost/spirit/home/karma/detail/pass_container.hpp, is_container<C> itself is used as MPL Boolean Constant, like traits::is_container<RHSAttribute>::value.

NOTE: Version field does not have 1.46.1, so I set it to 1.46.0.

[Hartmut Kaiser]

Sorry I do not understand your problem. boost::spirit::traits::is_container<> is derived from mpl::bool_<> (see $BOOST_ROOT/boost/spirit/home/support/contain.hpp). What's wrong with that?

[anonymous]

Replying to hkaiser:

Sorry I do not understand your problem. boost::spirit::traits::is_container<> is derived from mpl::bool_<> (see $BOOST_ROOT/boost/spirit/home/support/contain.hpp). What's wrong with that?

Sorry for unclarity. Implementation has no problem. The problem point is documentation. is_container is provided for customization point. A reader who wants to provide is_container can misunderstand providing type' is enough, according to the current documentation because "Expression Semantics" only mentions type'.

[Hartmut Kaiser]

Replying to anonymous:

Replying to hkaiser:

Sorry I do not understand your problem. boost::spirit::traits::is_container<> is derived from mpl::bool_<> (see $BOOST_ROOT/boost/spirit/home/support/contain.hpp). What's wrong with that?

Sorry for unclarity. Implementation has no problem. The problem point is documentation. is_container is provided for customization point. A reader who wants to provide is_container can misunderstand providing type' is enough, according to the current documentation because "Expression Semantics" only mentions type'.

The documentation clearly states that is_container<C>::type has to evaluate to an MPL boolean constant (see expression semantics here: http://www.boost.org/doc/libs/1_46_1/libs/spirit/doc/html/spirit/advanced/customize/is_container.html#spirit.advanced.customize.is_container.expression_semantics).