Fix evaluation of operations that return reducible terms (#293)

* correctly evaluate operations that return reducible terms

* switch to interpreter

Author: jfeser

effectful/ops/semantics.py

@@ -46,8 +46,10 @@ def apply(intp: Interpretation, op: Operation, *args, **kwargs) -> Any:
     mul(add(1, 2), 3)
 
     """
+    from effectful.internals.runtime import interpreter
+
     if op in intp:
-        return intp[op](*args, **kwargs)
+        return interpreter(intp)(intp[op])(*args, **kwargs)
     elif apply in intp:
         return intp[apply](intp, op, *args, **kwargs)
     else:

tests/test_ops_semantics.py

@@ -19,7 +19,7 @@
     runner,
     typeof,
 )
-from effectful.ops.syntax import ObjectInterpretation, Scoped, defop, implements
+from effectful.ops.syntax import ObjectInterpretation, Scoped, deffn, defop, implements
 from effectful.ops.types import Interpretation, Operation
 
 logger = logging.getLogger(__name__)
@@ -756,3 +756,17 @@ def box_value(x: T) -> Box[T]:
 
     # Generic types are simplified to their origin type
     assert typeof(box_value(42)) is Box
+
+
+def test_evaluate_deep():
+    x, y, z = defop(int), defop(int), defop(int)
+    intp = {x: deffn(1), y: deffn(2), z: deffn(x() + y())}
+
+    with handler(intp):
+        assert z() == 3
+
+    assert handler(intp)(z)() == 3
+
+    assert evaluate(evaluate(z(), intp=intp), intp=intp) == 3
+
+    assert evaluate(z(), intp=intp) == 3