# Adapt self to another local class context
# Useful for genericity
+ # 'c' Must be a super-class of self
+ # Example:
+ # class A[E]
+ # class B[F] special A[F]
+ # class C[G] special B[String]
+ # class D special C[Float]
+ # 'A[Int]'.upcast_for('A') -> 'A[Int]'
+ # 'A[Int]'.upcast_for('B') -> abort
+ # 'B[Int]'.upcast_for('B') -> 'B[Int]'
+ # 'B[Int]'.upcast_for('A') -> 'A[Int]'
+ # 'B[Int]'.upcast_for('C') -> abort
+ # 'C[Int]'.upcast_for('C') -> 'C[Int]'
+ # 'C[Int]'.upcast_for('B') -> 'B[String]'
+ # 'C[Int]'.upcast_for('A') -> 'A[String]'
+ # 'D'.upcast_for('D') -> 'D'
+ # 'D'.upcast_for('C') -> 'C[Float]'
+ # 'D'.upcast_for('B') -> 'C[String]'
+ # 'D'.upcast_for('A') -> 'A[String]'
meth upcast_for(c: MMLocalClass): MMType is abstract
# Return a type approximation if the reveiver is not self
# The type of null
class MMTypeNone
special MMType
- redef readable attr _module: MMModule
- redef meth <(t) do return true
- redef meth is_supertype(t) do return false
- redef meth local_class do abort
- redef meth upcast_for(c) do return self
+ redef readable attr _module: MMModule
+ redef meth <(t) do return true
+ redef meth to_s do return "null"
+ redef meth is_supertype(t) do return false
+ redef meth local_class do abort
+ redef meth upcast_for(c) do abort
private init(m: MMModule) do _module = m
end