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: «␤» 
Zape.HOW.say ; # OUTPUT: «␤» 

ParametricRoleHOWs need to be added to this kind of group:

my \zape := Metamodel::ParametricRoleGroupHOW.new_typename => "zape");
my \zipi := Metamodel::ParametricRoleHOW.new_typename => "zipi"group => zape);
say zipi.HOW# OUTPUT: «␤» 

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.