Implemented .pop() method for list

Author: xarus01

py/list.go

@@ -28,6 +28,22 @@ func init() {
 		return NoneType{}, nil
 	}, 0, "append(item)")
 
+	ListType.Dict["pop"] = MustNewMethod("pop", func(self Object, args Tuple) (Object, error) {
+		var index Object = Int(0)
+		listSelf := self.(*List)
+    err := UnpackTuple(args, nil, "pop", 0, 1, &index)
+    if err != nil {
+      return nil, err
+    }
+		i, err := IndexIntCheck(index, listSelf.Len())
+		if err != nil {
+			return nil, err
+		}
+		popElement := listSelf.Items[i]
+		listSelf.Items = append(listSelf.Items[:i], listSelf.Items[i+1:]...)
+		return popElement, nil
+	}, 0, "pop(index)")
+
 	ListType.Dict["extend"] = MustNewMethod("extend", func(self Object, args Tuple) (Object, error) {
 		listSelf := self.(*List)
 		if len(args) != 1 {

py/tests/list.py

@@ -35,6 +35,13 @@
 assert repr(a) == "['a', 'b', 'c', 'd', 'e', 'f']"
 assertRaises(TypeError, lambda: [].append())
 
+doc="pop"
+a = [1,2,3,4]
+assert a.pop() == 1
+assert a.pop(2) == 4
+assert repr(a) == "[2, 3]"
+assertRaises(IndexError, lambda: [].pop())
+
 doc="mul"
 a = [1, 2, 3]
 assert a * 2  == [1, 2, 3, 1, 2, 3]