@Override
public TypeResult typecheck(TypeEnv E) throws TypeError {
Logger.i("----------type check in App");
TypeResult tr1 = l.typecheck(E);
Logger.i("e1:" + tr1.t);
TypeResult tr2 = r.typecheck(E);
Logger.i("e2:" + tr2.t);
Type t1 = tr1.t;
Type t2 = tr2.t;
Substitution substitution = tr2.s.compose(tr1.s);
t1 = substitution.apply(t1);
t2 = substitution.apply(t2);
Type resultType;
if (t1 instanceof ArrowType) {
substitution = ((ArrowType) t1).t1.unify(t2).compose(substitution); // t1=t2->a
t1 = substitution.apply(t1);
resultType = ((ArrowType) t1).t2;
} else if (t1 instanceof TypeVar) {
TypeVar tv = new TypeVar(false); // new type a
substitution = t1.unify(new ArrowType(t2, tv)).compose(substitution);
resultType = substitution.apply(tv);
} else {
throw new TypeError("no function found");
}
Logger.i("----------end check in App");
return TypeResult.of(substitution, resultType); // return a
}
@Override
public TypeResult typecheck(TypeEnv E) throws TypeError {
TypeResult l_type = l.typecheck(E);
Substitution sub = l_type.s;
sub = sub.apply(l_type.t).unify(Type.BOOL).compose(sub);
TypeResult r_type = r.typecheck(sub.compose(E));
sub = r_type.s.compose(sub);
sub = sub.apply(r_type.t).unify(Type.BOOL).compose(sub);
return TypeResult.of(sub, Type.BOOL);
}