class X::Composition::NotComposable
src
class X::Composition::NotComposable is Exception { }
Thrown when trying to compose a type into a target type, but the composer type
cannot be used for composition (roles and enums are generally OK).
For example
class A { }
class B does A { }
dies with
===SORRY!===
A is not composable, so B cannot compose it
because does is reserved for role composition, and A is not a role,
nor something that knows how to turn into a role.
The fix is to either make A a role, or use inheritance
( class B is A { } ) instead.
Methods
target-name
method target-name() returns Str:D
Returns the name of the type that should be composed, but failed.
composer
method composer() returns Mu
Returns the type that should be composed into the target, but which isn't a
role.
