[feaLib] Parse feature blocks with useExtension keyword

Lib/fontTools/feaLib/ast.py

@@ -8,9 +8,9 @@ class FeatureFile(object):
 
 
 class FeatureBlock(object):
-    def __init__(self, location, name):
+    def __init__(self, location, name, use_extension):
         self.location = location
-        self.name = name
+        self.name, self.use_extension = name, use_extension
         self.statements = []
 
 

Lib/fontTools/feaLib/parser.py

@@ -287,7 +287,13 @@ class Parser(object):
         location = self.cur_token_location_
         tag = self.expect_tag_()
         vertical = (tag == "vkrn")
-        block = ast.FeatureBlock(location, tag)
+
+        use_extension = False
+        if self.next_token_ == "useExtension":
+            self.expect_keyword_("useExtension")
+            use_extension = True
+
+        block = ast.FeatureBlock(location, tag, use_extension)
         self.parse_block_(block, vertical)
         return block
 

Lib/fontTools/feaLib/parser_test.py

@@ -36,6 +36,16 @@ class ParserTest(unittest.TestCase):
         self.assertEqual(foo.y, 456)
         self.assertEqual(foo.contourpoint, 5)
 
+    def test_feature_block(self):
+        [liga] = self.parse("feature liga {} liga;").statements
+        self.assertEqual(liga.name, "liga")
+        self.assertFalse(liga.use_extension)
+
+    def test_feature_block_useExtension(self):
+        [liga] = self.parse("feature liga useExtension {} liga;").statements
+        self.assertEqual(liga.name, "liga")
+        self.assertTrue(liga.use_extension)
+
     def test_glyphclass(self):
         [gc] = self.parse("@dash = [endash emdash figuredash];").statements
         self.assertEqual(gc.name, "dash")
@@ -366,10 +376,6 @@ class ParserTest(unittest.TestCase):
             ParserError, "longer than 4 characters",
             self.parse, "languagesystem latn FOOBAR")
 
-    def test_feature_block(self):
-        [liga] = self.parse("feature liga {} liga;").statements
-        self.assertEqual(liga.name, "liga")
-
     def setUp(self):
         self.tempdir = None
         self.num_tempfiles = 0