simplifications, renaming, clarifications

[SVN r1700]

test/named_params_test.cpp

@@ -15,7 +15,7 @@ using boost::keywords;
 struct name_t : keyword<name_t>
 {
    // this should go in a wrapper type, like arg<keyword, predicate>
-   typedef boost::is_convertible<boost::mpl::_1, const char*> predicate_type;
+   typedef boost::is_convertible<boost::mpl::_1, const char*> predicate;
    using keyword<name_t>::operator=;
 } name;
 
@@ -71,6 +71,7 @@ int f(const Name& name_,
 
 }
 
+struct Foo { operator const char*() const { return "foo"; } };
 int main()
 {
    using test::f;
@@ -82,7 +83,7 @@ int main()
 #if BOOST_MSVC == 1200  // sadly templated operator= just doesn't work.
    f(index(56), name("foo"));
 #else 
-   f(index = 56, name = "foo");
+   f(index = 56, name = Foo());
 #endif 
    //f(index = 56, name = 55); // won't compile
    return 0;