From 7db9ba6ef6c33f2b84bf399c9d552aa7a0cfca1a Mon Sep 17 00:00:00 2001
From: Khaled Hosny <khaledhosny@eglug.org>
Date: Fri, 7 Aug 2020 17:57:23 +0200
Subject: [PATCH] [feaLib] Allow anonymous glyphclass in LookupFlags

Almost everywhere else when a glyph class name is accepted, anonymous
glyph classes are also accepted. This is rather inconsistent and
inconvenient.
---
 Lib/fontTools/feaLib/parser.py   | 17 ++---------------
 Tests/feaLib/data/lookupflag.fea | 10 ++++++++++
 Tests/feaLib/data/lookupflag.ttx | 27 ++++++++++++++++++++++++++-
 Tests/feaLib/parser_test.py      | 24 ++++++++++++++++++++++++
 4 files changed, 62 insertions(+), 16 deletions(-)

diff --git a/Lib/fontTools/feaLib/parser.py b/Lib/fontTools/feaLib/parser.py
index ab6928ff7..7439fbf34 100644
--- a/Lib/fontTools/feaLib/parser.py
+++ b/Lib/fontTools/feaLib/parser.py
@@ -408,19 +408,6 @@ class Parser(object):
         self.expect_symbol_("]")
         return glyphs
 
-    def parse_class_name_(self):
-        # Parses named class - either a glyph class or mark class.
-        name = self.expect_class_name_()
-        gc = self.glyphclasses_.resolve(name)
-        if gc is None:
-            raise FeatureLibError(
-                "Unknown glyph class @%s" % name, self.cur_token_location_
-            )
-        if isinstance(gc, self.ast.MarkClass):
-            return self.ast.MarkClassName(gc, location=self.cur_token_location_)
-        else:
-            return self.ast.GlyphClassName(gc, location=self.cur_token_location_)
-
     def parse_glyph_pattern_(self, vertical):
         # Parses a glyph pattern, including lookups and context, e.g.::
         #
@@ -633,10 +620,10 @@ class Parser(object):
             seen.add(self.next_token_)
             if self.next_token_ == "MarkAttachmentType":
                 self.expect_keyword_("MarkAttachmentType")
-                markAttachment = self.parse_class_name_()
+                markAttachment = self.parse_glyphclass_(accept_glyphname=False)
             elif self.next_token_ == "UseMarkFilteringSet":
                 self.expect_keyword_("UseMarkFilteringSet")
-                markFilteringSet = self.parse_class_name_()
+                markFilteringSet = self.parse_glyphclass_(accept_glyphname=False)
             elif self.next_token_ in flags:
                 value_seen = True
                 value = value | flags[self.expect_name_()]
diff --git a/Tests/feaLib/data/lookupflag.fea b/Tests/feaLib/data/lookupflag.fea
index 1828c43ed..0210ab42f 100644
--- a/Tests/feaLib/data/lookupflag.fea
+++ b/Tests/feaLib/data/lookupflag.fea
@@ -147,3 +147,13 @@ feature test {
         pos two 2;
     } X;
 } test;
+
+lookup Y {
+    lookupflag UseMarkFilteringSet [acute grave macron];
+    pos Y 1;
+} Y;
+
+lookup Z {
+    lookupflag MarkAttachmentType [acute grave macron];
+    pos Z 1;
+} Z;
diff --git a/Tests/feaLib/data/lookupflag.ttx b/Tests/feaLib/data/lookupflag.ttx
index 760eab313..16ea751f5 100644
--- a/Tests/feaLib/data/lookupflag.ttx
+++ b/Tests/feaLib/data/lookupflag.ttx
@@ -107,7 +107,7 @@
       </FeatureRecord>
     </FeatureList>
     <LookupList>
-      <!-- LookupCount=24 -->
+      <!-- LookupCount=26 -->
       <Lookup index="0">
         <LookupType value="1"/>
         <LookupFlag value="1"/><!-- rightToLeft -->
@@ -400,6 +400,31 @@
           <Value XAdvance="2"/>
         </SinglePos>
       </Lookup>
+      <Lookup index="24">
+        <LookupType value="1"/>
+        <LookupFlag value="16"/><!-- useMarkFilteringSet -->
+        <!-- SubTableCount=1 -->
+        <SinglePos index="0" Format="1">
+          <Coverage>
+            <Glyph value="Y"/>
+          </Coverage>
+          <ValueFormat value="4"/>
+          <Value XAdvance="1"/>
+        </SinglePos>
+        <MarkFilteringSet value="0"/>
+      </Lookup>
+      <Lookup index="25">
+        <LookupType value="1"/>
+        <LookupFlag value="256"/><!-- markAttachmentType[1] -->
+        <!-- SubTableCount=1 -->
+        <SinglePos index="0" Format="1">
+          <Coverage>
+            <Glyph value="Z"/>
+          </Coverage>
+          <ValueFormat value="4"/>
+          <Value XAdvance="1"/>
+        </SinglePos>
+      </Lookup>
     </LookupList>
   </GPOS>
 
diff --git a/Tests/feaLib/parser_test.py b/Tests/feaLib/parser_test.py
index 580902969..db505950c 100644
--- a/Tests/feaLib/parser_test.py
+++ b/Tests/feaLib/parser_test.py
@@ -718,6 +718,18 @@ class ParserTest(unittest.TestCase):
         self.assertEqual(flag.asFea(),
             "lookupflag RightToLeft MarkAttachmentType @TOP_MARKS;")
 
+    def test_lookupflag_format_A_MarkAttachmentType_glyphClass(self):
+        flag = self.parse_lookupflag_(
+            "lookupflag RightToLeft MarkAttachmentType [acute grave macron];")
+        self.assertIsInstance(flag, ast.LookupFlagStatement)
+        self.assertEqual(flag.value, 1)
+        self.assertIsInstance(flag.markAttachment, ast.GlyphClass)
+        self.assertEqual(flag.markAttachment.glyphSet(),
+                         ("acute", "grave", "macron"))
+        self.assertIsNone(flag.markFilteringSet)
+        self.assertEqual(flag.asFea(),
+            "lookupflag RightToLeft MarkAttachmentType [acute grave macron];")
+
     def test_lookupflag_format_A_UseMarkFilteringSet(self):
         flag = self.parse_lookupflag_(
             "@BOTTOM_MARKS = [cedilla ogonek];"
@@ -731,6 +743,18 @@ class ParserTest(unittest.TestCase):
         self.assertEqual(flag.asFea(),
             "lookupflag IgnoreLigatures UseMarkFilteringSet @BOTTOM_MARKS;")
 
+    def test_lookupflag_format_A_UseMarkFilteringSet_glyphClass(self):
+        flag = self.parse_lookupflag_(
+            "lookupflag UseMarkFilteringSet [cedilla ogonek] IgnoreLigatures;")
+        self.assertIsInstance(flag, ast.LookupFlagStatement)
+        self.assertEqual(flag.value, 4)
+        self.assertIsNone(flag.markAttachment)
+        self.assertIsInstance(flag.markFilteringSet, ast.GlyphClass)
+        self.assertEqual(flag.markFilteringSet.glyphSet(),
+                         ("cedilla", "ogonek"))
+        self.assertEqual(flag.asFea(),
+            "lookupflag IgnoreLigatures UseMarkFilteringSet [cedilla ogonek];")
+
     def test_lookupflag_format_B(self):
         flag = self.parse_lookupflag_("lookupflag 7;")
         self.assertIsInstance(flag, ast.LookupFlagStatement)