Rules / Types, classes & roles / metamodel

Metamodel::ParametricRoleGroupHOW Reference

Represents a group of roles with different parameterizations

What it is #

Examples, run three ways #

Every example below comes from the official documentation, together with the output that documentation asserts. Each was then executed by Rakudo and by Raku++ when this page was built. Where the three agree, one result is shown; where they do not, all three are — because which of them is wrong is exactly the information worth having.

1 no-output · 2 rakupp-differs

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

Not executed: the documentation states no expected output for this example.

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

Raku++ disagrees with both the documentation and Rakudo — a defect.

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␤»
Documentation
Perl6::Metamodel::ParametricRoleHOW.new
Rakudo
Perl6::Metamodel::ParametricRoleHOW.new
Raku++
(Metamodel::ClassHOW)

Raku++ disagrees with both the documentation and Rakudo — a defect.