From 3936e334f1e8ae3d52bd689027e39668afd465b0 Mon Sep 17 00:00:00 2001
From: Sascha Brawer <sascha@brawer.ch>
Date: Sat, 1 Aug 2015 19:25:48 +0200
Subject: [PATCH] [feaLib] Resolve references to glyph classes

---
 Lib/fontTools/feaLib/parser.py      | 23 +++++++++++++++++++--
 Lib/fontTools/feaLib/parser_test.py | 32 ++++++++++++++++++++++-------
 2 files changed, 46 insertions(+), 9 deletions(-)

diff --git a/Lib/fontTools/feaLib/parser.py b/Lib/fontTools/feaLib/parser.py
index 0f896ed03..9cc4d1dd2 100644
--- a/Lib/fontTools/feaLib/parser.py
+++ b/Lib/fontTools/feaLib/parser.py
@@ -66,10 +66,19 @@ class Parser(object):
 
     def parse_glyphclass_reference_(self):
         result = set()
+        if self.next_token_type_ is Lexer.GLYPHCLASS:
+            self.advance_lexer_()
+            gc = self.resolve_glyphclass_(self.cur_token_)
+            if gc is None:
+                raise ParserError("Unknown glyph class @%s" % self.cur_token_,
+                                  self.cur_token_location_)
+            result.update(gc.glyphs)
+            return result
+
         self.expect_symbol_("[")
         while self.next_token_ != "]":
-            if self.next_token_type_ is Lexer.NAME:
-                self.advance_lexer_()
+            self.advance_lexer_()
+            if self.cur_token_type_ is Lexer.NAME:
                 if self.next_token_ == "-":
                     range_location_ = self.cur_token_location_
                     range_start = self.cur_token_
@@ -80,6 +89,16 @@ class Parser(object):
                                                          range_end))
                 else:
                     result.add(self.cur_token_)
+            elif self.cur_token_type_ is Lexer.GLYPHCLASS:
+                gc = self.resolve_glyphclass_(self.cur_token_)
+                if gc is None:
+                    raise ParserError(
+                        "Unknown glyph class @%s" % self.cur_token_,
+                        self.cur_token_location_)
+                result.update(gc.glyphs)
+            else:
+                raise ParserError("Expected glyph name, range, or reference",
+                                  self.cur_token_location_)
         self.expect_symbol_("]")
         return result
 
diff --git a/Lib/fontTools/feaLib/parser_test.py b/Lib/fontTools/feaLib/parser_test.py
index 40ae89183..80187215a 100644
--- a/Lib/fontTools/feaLib/parser_test.py
+++ b/Lib/fontTools/feaLib/parser_test.py
@@ -24,11 +24,26 @@ class ParserTest(unittest.TestCase):
         self.assertEqual(gc.name, "dash")
         self.assertEqual(gc.glyphs, {"endash", "emdash", "figuredash"})
 
+    def test_glyphclass_bad(self):
+        self.assertRaisesRegex(
+            ParserError, "Expected glyph name, range, or reference",
+            self.parse, "@bad = [a 123];")
+
     def test_glyphclass_duplicate(self):
         self.assertRaisesRegex(
             ParserError, "Glyph class @dup already defined",
             self.parse, "@dup = [a b]; @dup = [x];")
 
+    def test_glyphclass_empty(self):
+        [gc] = self.parse("@empty_set = [];").statements
+        self.assertEqual(gc.name, "empty_set")
+        self.assertEqual(gc.glyphs, set())
+
+    def test_glyphclass_equality(self):
+        [foo, bar] = self.parse("@foo = [a b]; @bar = @foo;").statements
+        self.assertEqual(foo.glyphs, {"a", "b"})
+        self.assertEqual(bar.glyphs, {"a", "b"})
+
     def test_glyphclass_range_uppercase(self):
         [gc] = self.parse("@swashes = [X.swash-Z.swash];").statements
         self.assertEqual(gc.name, "swashes")
@@ -72,13 +87,16 @@ class ParserTest(unittest.TestCase):
             "a", "foo.09", "foo.10", "foo.11", "X.sc", "Y.sc", "Z.sc"
         })
 
-    # TODO: self.parse("@foo = [a b]; @bar = [@foo];")
-    # TODO: self.parse("@foo = [a b]; @bar = @foo;")
-
-    def test_glyphclass_empty(self):
-        [gc] = self.parse("@empty_set = [];").statements
-        self.assertEqual(gc.name, "empty_set")
-        self.assertEqual(gc.glyphs, set())
+    def test_glyphclass_reference(self):
+        [vowels_lc, vowels_uc, vowels] = self.parse(
+            "@Vowels.lc = [a e i o u]; @Vowels.uc = [A E I O U]; " +
+            "@Vowels = [@Vowels.lc @Vowels.uc y Y];").statements
+        self.assertEqual(vowels_lc.glyphs, set(list("aeiou")))
+        self.assertEqual(vowels_uc.glyphs, set(list("AEIOU")))
+        self.assertEqual(vowels.glyphs, set(list("aeiouyAEIOUY")))
+        self.assertRaisesRegex(
+            ParserError, "Unknown glyph class @unknown",
+            self.parse, "@bad = [@unknown];")
 
     def test_languagesystem(self):
         [langsys] = self.parse("languagesystem latn DEU;").statements