define type declarators

Author: gfldex

doc/Language/typesystem.pod6

@@ -27,7 +27,21 @@ method C<.defined> can be overloaded and may provide false information.
 
 =head1 Type Declarators
 
-TODO
+Type declarators introduce a new type into the given scope. Nested scopes can
+be separated by C<::>. New L<packages|/language/packages> are created
+automatically if no such scope exists already.
+
+    class Foo::Bar::C {};
+    put Foo::Bar::.keys;
+    # OUTPUT«C␤»
+
+X«|... (forward declaration)»
+X«Forward declarations» can be provided with a block containing only C<...>. The
+compiler will check at the end of the current scope if the type is defined.
+
+    class C {...}
+    # many lines later
+    class C { has $.attr }
 
 =head2 C<class>