txt: ## parametricrolegrouphow.md
  role Metamodel::ParametricRoleGroupHOW
  
  Represents a group of roles with different parameterizations
  
  ```raku
  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.
  
  ```raku
  (role Zape[::T] {}).HOW.say; # OUTPUT: «Perl6::Metamodel::ParametricRoleHOW.new␤»
  Zape.HOW.say ; # OUTPUT: «Perl6::Metamodel::ParametricRoleGroupHOW.new␤»
  
  ```
  
  `ParametricRoleHOW`s need to be added to this kind of group:
  
  ```raku
  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.
  