Implemented isinstance

Author: xarus01

builtin/builtin.go

@@ -44,7 +44,7 @@ func init() {
 		// py.MustNewMethod("hex", builtin_hex, 0, hex_doc),
 		// py.MustNewMethod("id", builtin_id, 0, id_doc),
 		// py.MustNewMethod("input", builtin_input, 0, input_doc),
-		// py.MustNewMethod("isinstance", builtin_isinstance, 0, isinstance_doc),
+		py.MustNewMethod("isinstance", builtin_isinstance, 0, isinstance_doc),
 		// py.MustNewMethod("issubclass", builtin_issubclass, 0, issubclass_doc),
 		py.MustNewMethod("iter", builtin_iter, 0, iter_doc),
 		py.MustNewMethod("len", builtin_len, 0, len_doc),
@@ -826,6 +826,50 @@ object.
 The globals and locals are dictionaries, defaulting to the current
 globals and locals.  If only globals is given, locals defaults to it.`
 
+const isinstance_doc = `isinstance(obj, class_or_tuple) -> bool
+
+Return whether an object is an instance of a class or of a subclass thereof.
+
+A tuple, as in isinstance(x, (A, B, ...)), may be given as the target to
+check against. This is equivalent to isinstance(x, A) or isinstance(x, B)
+or ... etc.
+`
+
+func isinstance(args py.Tuple) (py.Bool, error) {
+	switch args[1].(type) {
+	case py.Tuple:
+		{
+			var res py.Bool
+			var class = args[1].(py.Tuple)
+			for idx := range class {
+				var new_args []py.Object
+				new_args = append(new_args, args[0], class[idx])
+				temp, err := isinstance(new_args)
+				if err != nil {
+					return false, err
+				}
+				res = res || temp
+			}
+			return res, nil
+		}
+	default:
+		{
+			if args[0].Type() != py.TypeType {
+				return false, py.ExceptionNewf(py.TypeError, "isinstance() arg 2 must be a type or tuple of types")
+			}
+			return args[0].Type() == args[1], nil
+		}
+	}
+}
+
+func builtin_isinstance(self py.Object, args py.Tuple) (py.Object, error) {
+	if len(args) > 2 {
+		return nil, py.ExceptionNewf(py.TypeError, "isinstance expected 2 arguments, got %d", len(args))
+	}
+
+	return isinstance(args)
+}
+
 const iter_doc = `iter(iterable) -> iterator
 iter(callable, sentinel) -> iterator
 

go.mod

@@ -4,3 +4,5 @@ require (
 	github.com/gopherjs/gopherwasm v1.0.0 // indirect
 	github.com/peterh/liner v1.1.0
 )
+
+go 1.13

vm/tests/builtin.py

@@ -65,4 +65,25 @@
 else:
     assert False, "SyntaxError not raised"
 
+doc="isinstance"
+class A:
+    pass
+a = A()
+assert True, isinstance(1, (str, tuple, int))
+assert True, isinstance(a, (str, (tuple, (A, ))))
+
+try:
+    isinstance(1, (A, ), "foo")
+except TypeError:
+    pass
+else:
+    assert False, "TypeError not raised"
+
+try:
+    isinstance(1, (A, "foo"))
+except TypeError:
+    pass
+else:
+    assert False, "TypeError not raised"
+
 doc="finished"