[feaLib] Make feaLib compliant with the PEP8 style guide

After this change, pep8 v1.6.2 reports no style guide violations.

Lib/fontTools/feaLib/lexer_test.py

@@ -80,15 +80,16 @@ class LexerTest(unittest.TestCase):
         self.assertRaises(FeatureLibError, lambda: lex("123 \u0001"))
 
     def test_newline(self):
-        lines = lambda s: [loc[1] for (_, _, loc) in Lexer(s, "test.fea")]
+        def lines(s):
+            return [loc[1] for (_, _, loc) in Lexer(s, "test.fea")]
         self.assertEqual(lines("FOO\n\nBAR\nBAZ"), [1, 3, 4])  # Unix
         self.assertEqual(lines("FOO\r\rBAR\rBAZ"), [1, 3, 4])  # Macintosh
         self.assertEqual(lines("FOO\r\n\r\n BAR\r\nBAZ"), [1, 3, 4])  # Windows
         self.assertEqual(lines("FOO\n\rBAR\r\nBAZ"), [1, 3, 4])  # mixed
 
     def test_location(self):
-        locs = lambda s: ["%s:%d:%d" % loc
-                          for (_, _, loc) in Lexer(s, "test.fea")]
+        def locs(s):
+            return ["%s:%d:%d" % loc for (_, _, loc) in Lexer(s, "test.fea")]
         self.assertEqual(locs("a b # Comment\n12 @x"), [
             "test.fea:1:1", "test.fea:1:3", "test.fea:2:1",
             "test.fea:2:4"

Lib/fontTools/feaLib/parser.py

@@ -400,6 +400,11 @@ class Parser(object):
         except StopIteration:
             self.next_token_type_, self.next_token_ = (None, None)
 
+    @staticmethod
+    def reverse_string_(s):
+        """'abc' --> 'bca'"""
+        return ''.join(reversed(list(s)))
+
     def make_glyph_range_(self, location, start, limit):
         """("a.sc", "d.sc") --> {"a.sc", "b.sc", "c.sc", "d.sc"}"""
         result = set()
@@ -407,7 +412,8 @@ class Parser(object):
             raise FeatureLibError(
                 "Bad range: \"%s\" and \"%s\" should have the same length" %
                 (start, limit), location)
-        rev = lambda s: ''.join(reversed(list(s)))  # string reversal
+
+        rev = self.reverse_string_
         prefix = os.path.commonprefix([start, limit])
         suffix = rev(os.path.commonprefix([rev(start), rev(limit)]))
         if len(suffix) > 0: