[feaLib] Move block parsing to a separate method

We will soon support additional blocks beyond `feature`,
and keeping this refactoring separate from new functionality
makes it easier for code reviewers to follow the changes.

Lib/fontTools/feaLib/ast.py

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

Lib/fontTools/feaLib/parser.py

@@ -43,7 +43,7 @@ class Parser(object):
             elif self.is_cur_keyword_("languagesystem"):
                 self.parse_languagesystem_()
             elif self.is_cur_keyword_("feature"):
-                self.parse_feature_block_()
+                statements.append(self.parse_feature_block_())
             else:
                 raise ParserError("Expected languagesystem, feature, or "
                                   "glyph class definition",
@@ -214,15 +214,16 @@ class Parser(object):
         location = self.cur_token_location_
         tag = self.expect_tag_()
         vertical = (tag == "vkrn")
+        block = ast.FeatureBlock(location, tag)
+        self.parse_block_(block, vertical)
+        return block
 
+    def parse_block_(self, block, vertical):
         self.expect_symbol_("{")
         for symtab in self.symbol_tables_:
             symtab.enter_scope()
 
-        block = ast.FeatureBlock(location, tag)
-        self.doc_.statements.append(block)
         statements = block.statements
-
         while self.next_token_ != "}":
             self.advance_lexer_()
             if self.cur_token_type_ is Lexer.GLYPHCLASS:
@@ -248,9 +249,9 @@ class Parser(object):
         for symtab in self.symbol_tables_:
             symtab.exit_scope()
 
-        endtag = self.expect_tag_()
+        name = self.expect_name_()
-        if tag != endtag:
+        if name != block.name.strip():
-            raise ParserError("Expected \"%s\"" % tag.strip(),
+            raise ParserError("Expected \"%s\"" % block.name.strip(),
                               self.cur_token_location_)
         self.expect_symbol_(";")
 

Lib/fontTools/feaLib/parser_test.py

@@ -286,7 +286,7 @@ class ParserTest(unittest.TestCase):
 
     def test_feature_block(self):
         [liga] = self.parse("feature liga {} liga;").statements
-        self.assertEqual(liga.tag, "liga")
+        self.assertEqual(liga.name, "liga")
 
     def setUp(self):
         self.tempdir = None