set: Implement initialization set with sequence (#100)

* set: Implement initialization set with sequence

* Remove comment

* Remove typo

* set: Improve test code

Author: SanggiHong

py/sequence.go

@@ -43,6 +43,26 @@ func SequenceList(v Object) (*List, error) {
 	}
 }
 
+// Converts a sequence object v into a Set
+func SequenceSet(v Object) (*Set, error) {
+	switch x := v.(type) {
+	case Tuple:
+		return NewSetFromItems(x), nil
+	case *List:
+		return NewSetFromItems(x.Items), nil
+	default:
+		s := NewSet()
+		err := Iterate(v, func(item Object) bool {
+			s.Add(item)
+			return false
+		})
+		if err != nil {
+			return nil, err
+		}
+		return s, nil
+	}
+}
+
 // Call __next__ for the python object
 //
 // Returns the next object

py/set.go

@@ -56,11 +56,10 @@ func SetNew(metatype *Type, args Tuple, kwargs StringDict) (Object, error) {
 	if err != nil {
 		return nil, err
 	}
-	if iterable == nil {
-		return NewSet(), nil
+	if iterable != nil {
+		return SequenceSet(iterable)
 	}
-	// FIXME should be able to initialise from an iterable!
-	return NewSetFromItems(iterable.(Tuple)), nil
+	return NewSet(), nil
 }
 
 var FrozenSetType = NewType("frozenset", "frozenset() -> empty frozenset object\nfrozenset(iterable) -> frozenset object\n\nBuild an immutable unordered collection of unique elements.")

py/tests/set.py

@@ -55,6 +55,20 @@
 
 d = a ^ b
 assert 1 in c
+
+doc="set"
+a = set([1,2,3])
+b = set("set")
+c = set((4,5))
+assert len(a) == 3
+assert len(b) == 3
+assert len(c) == 2
+assert 1 in a
+assert 2 in a
+assert 3 in a
+assert "s" in b
+assert "e" in b
+assert "t" in b
 assert 4 in c
 assert 5 in c