module Foo
imports int String char
abstract syntax

T1 implemented by Object = f(x:T2,y:T1) | a(x:T2)
T2 implemented by Object = g(x:T1,y:T2) | b()
T3 implemented by Map<Int,Int> = S(x:String)
T4 implemented by java.lang.Object = T(x:char)

List implemented by Object = List(T1*)
IList implemented by Object = iList(int*)
IList2 implemented by Object = iList21(int*) | iList22(int*)