Merge "Allow Sequence/Iterable/Iterator to be nullable"

yaql/language/yaqltypes.py

@@ -166,9 +166,9 @@ class DateTime(PythonType):
 
 
 class Iterable(PythonType):
-    def __init__(self, validators=None):
+    def __init__(self, validators=None, nullable=False):
         super(Iterable, self).__init__(
-            collections.Iterable, False, [
+            collections.Iterable, nullable, [
                 lambda t: not isinstance(t, six.string_types + (
                     utils.MappingType,))] + (validators or []))
 
@@ -183,19 +183,20 @@ class Iterable(PythonType):
                 *args, **kwargs):
         res = super(Iterable, self).convert(
             value, receiver, context, function_spec, engine, *args, **kwargs)
-        return utils.limit_iterable(res, engine)
+        return None if res is None else utils.limit_iterable(res, engine)
 
 
 class Iterator(Iterable):
-    def __init__(self, validators=None):
+    def __init__(self, validators=None, nullable=False):
         super(Iterator, self).__init__(
-            validators=[utils.is_iterator] + (validators or []))
+            validators=[utils.is_iterator] + (validators or []),
+            nullable=nullable)
 
 
 class Sequence(PythonType):
-    def __init__(self, validators=None):
+    def __init__(self, validators=None, nullable=False):
         super(Sequence, self).__init__(
-            collections.Sequence, False, [
+            collections.Sequence, nullable, [
                 lambda t: not isinstance(t, six.string_types + (dict,))] + (
                     validators or []))
 

yaql/tests/test_miscellaneous.py

@@ -30,3 +30,52 @@ class TestMiscellaneous(yaql.tests.TestCase):
         self.assertRaises(
             exceptions.NoMatchingFunctionException,
             self.eval, 'foo(true)')
+
+    def test_nullable_collections(self):
+        @specs.parameter('arg', yaqltypes.Sequence())
+        def foo1(arg):
+            return arg is None
+
+        @specs.parameter('arg', yaqltypes.Sequence(nullable=True))
+        def foo2(arg):
+            return arg is None
+
+        @specs.parameter('arg', yaqltypes.Iterable())
+        def bar1(arg):
+            return arg is None
+
+        @specs.parameter('arg', yaqltypes.Iterable(nullable=True))
+        def bar2(arg):
+            return arg is None
+
+        @specs.parameter('arg', yaqltypes.Iterator())
+        def baz1(arg):
+            return arg is None
+
+        @specs.parameter('arg', yaqltypes.Iterator(nullable=True))
+        def baz2(arg):
+            return arg is None
+
+        for func in (foo1, foo2, bar1, bar2, baz1, baz2):
+            self.context.register_function(func)
+
+        self.assertFalse(self.eval('foo1([1, 2])'))
+        self.assertRaises(
+            exceptions.NoMatchingFunctionException,
+            self.eval, 'foo1(null)')
+        self.assertFalse(self.eval('foo2([1, 2])'))
+        self.assertTrue(self.eval('foo2(null)'))
+
+        self.assertFalse(self.eval('bar1([1, 2])'))
+        self.assertRaises(
+            exceptions.NoMatchingFunctionException,
+            self.eval, 'bar1(null)')
+        self.assertFalse(self.eval('bar2([1, 2])'))
+        self.assertTrue(self.eval('bar2(null)'))
+
+        self.assertFalse(self.eval('baz1($)', data=iter([1, 2])))
+        self.assertRaises(
+            exceptions.NoMatchingFunctionException,
+            self.eval, 'baz1(null)')
+        self.assertFalse(self.eval('baz2($)', data=iter([1, 2])))
+        self.assertTrue(self.eval('baz2(null)'))