class Metamodel::ParametricRoleGroupHOW
    does Metamodel::Naming
    does Metamodel::Documenting
    does Metamodel::Stashing
    does Metamodel::TypePretense
    does Metamodel::RolePunning
    does Metamodel::BoolificationProtocol {}

Warning: this role is part of the Rakudo implementation, and is not a part of the language specification.

A ParametricRoleGroupHOW groups a set of ParametricRoleHOW, every one of them representing a single role declaration with their own parameter sets.

(role Zape[::T] {}).HOW.say; # OUTPUT: «Perl6::Metamodel::ParametricRoleHOW.new␤»
Zape.HOW.say ; # OUTPUT: «Perl6::Metamodel::ParametricRoleGroupHOW.new␤»

ParametricRoleHOWs need to be added to this kind of group:

my \zape := Metamodel::ParametricRoleGroupHOW.new_type( name => "zape");
my \zipi := Metamodel::ParametricRoleHOW.new_type( name => "zipi", group => zape);
say zipi.HOW; # OUTPUT: «Perl6::Metamodel::ParametricRoleHOW.new␤»

Note: As most of the Metamodel classes, this class is here mainly for illustration purposes and it's not intended for the final user to instantiate.