Don't use recursion in evaluate :(

silly_thing.py

@@ -28,15 +28,14 @@ def evaluate(expr: Expression) -> Expression:
 	>>> evaluate(Application((funktion, Int(0))))
 	1312
 	"""
-	if expr.is_value():
-		return expr
-	else:
+	while not expr.is_value():
 		match expr.step():
 			case Some(next):
-				return evaluate(next)
+				expr = next
+				# Loop
 			case None:
 				raise AssertionError('Evaluate called on a value which cannot step:', expr)
-	raise Exception('Unreachable')
+	return expr
 
 def repl_expr(expr: Expression, bindings: ReplHole = ReplHole(BUILTINS_CONTEXT)):
 	expr_subst = subst_all(bindings.val_bindings, expr)