[feaLib] Support stylistic set featureNames

Does not handle featureNames for cvXX features, but it shouldn’t be hard
for someone to extend the code to support them if inclined to do so.

Lib/fontTools/feaLib/ast.py

@@ -591,3 +591,8 @@ class NameRecord(Statement):
         builder.add_name_record(
             self.location, self.nameID, self.platformID,
             self.platEncID, self.langID, self.string)
+
+class FeatureNameStatement(NameRecord):
+    def build(self, builder):
+        NameRecord.build(self, builder)
+        builder.add_featureName(self.location, self.nameID)

Lib/fontTools/feaLib/builder.py

@@ -35,6 +35,9 @@ class Builder(object):
         self.aalt_features_ = []  # [(location, featureName)*], for 'aalt'
         self.aalt_location_ = None
         self.aalt_alternates_ = {}
+        # for 'featureNames'
+        self.featureNames_ = []
+        self.featureNames_ids_ = {}
         # for table 'head'
         self.fontRevision_ = None  # 2.71
         # for table 'name'
@@ -157,14 +160,38 @@ class Builder(object):
             table.created = table.modified = 3406620153  # 2011-12-13 11:22:33
         table.fontRevision = self.fontRevision_
 
+    def get_user_name_id(self, table):
+        # Try to find first unused font-specific name id
+        nameIDs = [name.nameID for name in table.names]
+        for user_name_id in range(256, 32767):
+            if user_name_id not in nameIDs:
+                return user_name_id
+
+    def buildFeatureParams(self, tag):
+        params = None
+        if tag in self.featureNames_:
+            assert tag in self.featureNames_ids_
+            params = otTables.FeatureParamsStylisticSet()
+            params.Version = 0
+            params.UINameID = self.featureNames_ids_[tag]
+        return params
+
     def build_name(self):
         if not self.names_:
             return
         table = self.font.get("name")
         if not table:  # this only happens for unit tests
             table = self.font["name"] = getTableClass("name")()
+            table.names = []
         for name in self.names_:
             nameID, platformID, platEncID, langID, string = name
+            if not isinstance(nameID, int):
+                # A featureNames name and nameID is actually the tag
+                tag = nameID
+                if tag not in self.featureNames_ids_:
+                    self.featureNames_ids_[tag] = self.get_user_name_id(table)
+                    assert self.featureNames_ids_[tag] is not None
+                nameID = self.featureNames_ids_[tag]
             table.setName(string, nameID, platformID, platEncID, langID)
 
     def buildGDEF(self):
@@ -276,7 +303,8 @@ class Builder(object):
                 frec = otTables.FeatureRecord()
                 frec.FeatureTag = feature_tag
                 frec.Feature = otTables.Feature()
-                frec.Feature.FeatureParams = None
+                frec.Feature.FeatureParams = self.buildFeatureParams(
+                                                feature_tag)
                 frec.Feature.LookupListIndex = lookup_indices
                 frec.Feature.LookupCount = len(lookup_indices)
                 table.FeatureList.FeatureRecord.append(frec)
@@ -523,6 +551,9 @@ class Builder(object):
                 location)
         self.aalt_features_.append((location, featureName))
 
+    def add_featureName(self, location, tag):
+        self.featureNames_.append(tag)
+
     def add_ligature_subst(self, location,
                            prefix, glyphs, suffix, replacement, forceChain):
         if prefix or suffix or forceChain:

Lib/fontTools/feaLib/builder_test.py

@@ -56,7 +56,7 @@ class BuilderTest(unittest.TestCase):
         spec4h1 spec5d1 spec5d2 spec5fi1 spec5fi2 spec5fi3 spec5fi4
         spec5f_ii_1 spec5f_ii_2 spec5f_ii_3 spec5f_ii_4
         spec5h1 spec6b_ii spec6d2 spec6e spec6f
-        spec6h_ii spec6h_iii_1 spec6h_iii_3d spec8a
+        spec6h_ii spec6h_iii_1 spec6h_iii_3d spec8a spec8c
         spec9b spec9c1 spec9c2 spec9c3 spec9e
         bug453 bug463 bug501 bug502 bug505 bug506 bug509 bug512
         name

Lib/fontTools/feaLib/parser.py

@@ -726,16 +726,7 @@ class Parser(object):
                 raise FeatureLibError("Expected nameid",
                                       self.cur_token_location_)
 
-    def parse_nameid_(self):
+    def parse_name_(self):
-        assert self.cur_token_ == "nameid", self.cur_token_
-        location, nameID = self.cur_token_location_, self.expect_number_()
-        if nameID > 255:
-            raise FeatureLibError("Expected name id < 255",
-                                  self.cur_token_location_)
-        if 1 <= nameID <= 6:
-            # TODO: issue a warning
-            return None
-
         platEncID = None
         langID = None
         if self.next_token_type_ == Lexer.NUMBER:
@@ -764,8 +755,21 @@ class Parser(object):
         elif platformID == 3 and platEncID == 1:
             string = self.unescape_windows_name_string(string)
 
-        return ast.NameRecord(location, nameID, platformID,
+        return platformID, platEncID, langID, string
-                              platEncID, langID, string)
+
+    def parse_nameid_(self):
+        assert self.cur_token_ == "nameid", self.cur_token_
+        location, nameID = self.cur_token_location_, self.expect_number_()
+        if nameID > 255:
+            raise FeatureLibError("Expected name id < 255",
+                                  self.cur_token_location_)
+        if 1 <= nameID <= 6:
+            # TODO: issue a warning
+            return None
+
+        platformID, platEncID, langID, string = self.parse_name_()
+        return ast.NameRecord(location, nameID, platformID, platEncID,
+                              langID, string)
 
     def unescape_mac_name_string(self, string):
         def unescape(match):
@@ -881,6 +885,9 @@ class Parser(object):
         location = self.cur_token_location_
         tag = self.expect_tag_()
         vertical = (tag in {"vkrn", "vpal", "vhal", "valt"})
+        stylisticset = None
+        if tag in ["ss%02d" % i for i in range(1, 20+1)]:
+            stylisticset = tag
 
         use_extension = False
         if self.next_token_ == "useExtension":
@@ -888,7 +895,7 @@ class Parser(object):
             use_extension = True
 
         block = ast.FeatureBlock(location, tag, use_extension)
-        self.parse_block_(block, vertical)
+        self.parse_block_(block, vertical, stylisticset)
         return block
 
     def parse_feature_reference_(self):
@@ -898,6 +905,30 @@ class Parser(object):
         self.expect_symbol_(";")
         return ast.FeatureReferenceStatement(location, featureName)
 
+    def parse_featureNames_(self, tag):
+        assert self.cur_token_ == "featureNames", self.cur_token_
+        self.expect_symbol_("{")
+        for symtab in self.symbol_tables_:
+            symtab.enter_scope()
+
+        statements = []
+        while self.next_token_ != "}":
+            self.expect_keyword_("name")
+            location = self.cur_token_location_
+            platformID, platEncID, langID, string = self.parse_name_()
+            statements.append(
+                    ast.FeatureNameStatement(location, tag, platformID,
+                                             platEncID, langID, string))
+
+        self.expect_symbol_("}")
+
+        for symtab in self.symbol_tables_:
+            symtab.exit_scope()
+
+        self.expect_symbol_(";")
+
+        return statements
+
     def parse_FontRevision_(self):
         assert self.cur_token_ == "FontRevision", self.cur_token_
         location, version = self.cur_token_location_, self.expect_float_()
@@ -907,7 +938,7 @@ class Parser(object):
                                   location)
         return ast.FontRevisionStatement(location, version)
 
-    def parse_block_(self, block, vertical):
+    def parse_block_(self, block, vertical, stylisticset=None):
         self.expect_symbol_("{")
         for symtab in self.symbol_tables_:
             symtab.enter_scope()
@@ -945,6 +976,8 @@ class Parser(object):
                 statements.append(self.parse_subtable_())
             elif self.is_cur_keyword_("valueRecordDef"):
                 statements.append(self.parse_valuerecord_definition_(vertical))
+            elif stylisticset and self.is_cur_keyword_("featureNames"):
+                statements.extend(self.parse_featureNames_(stylisticset))
             elif self.cur_token_ == ";":
                 continue
             else:

Lib/fontTools/feaLib/testdata/spec8c.fea

@@ -0,0 +1,11 @@
+ feature ss01 {
+    featureNames {
+         name "Feature description for MS Platform, script Unicode, language English";
+# With no platform ID, script ID, or language ID specified, the implementation assumes (3,1,0x409).
+         name 3 1 0x411 "Feature description for MS Platform, script Unicode, language Japanese";
+         name 1 "Feature description for Apple Platform, script Roman, language unspecified";
+# With only the platform ID specified, the implementation assumes script and language = Latin. For Apple this is (1,0,0).
+         name 1 1 12 "Feature description for Apple Platform, script Japanese, language Japanese";     } ;
+# --- rules for this feature ---
+    sub A by B;
+  } ss01;

Lib/fontTools/feaLib/testdata/spec8c.ttx

@@ -0,0 +1,62 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<ttFont>
+
+  <name>
+    <namerecord nameID="256" platformID="3" platEncID="1" langID="0x409">
+      Feature description for MS Platform, script Unicode, language English
+    </namerecord>
+    <namerecord nameID="256" platformID="3" platEncID="1" langID="0x411">
+      Feature description for MS Platform, script Unicode, language Japanese
+    </namerecord>
+    <namerecord nameID="256" platformID="1" platEncID="0" langID="0x0" unicode="True">
+      Feature description for Apple Platform, script Roman, language unspecified
+    </namerecord>
+    <namerecord nameID="256" platformID="1" platEncID="1" langID="0xc" unicode="True">
+      Feature description for Apple Platform, script Japanese, language Japanese
+    </namerecord>
+  </name>
+
+  <GSUB>
+    <Version value="1.0"/>
+    <ScriptList>
+      <!-- ScriptCount=1 -->
+      <ScriptRecord index="0">
+        <ScriptTag value="DFLT"/>
+        <Script>
+          <DefaultLangSys>
+            <ReqFeatureIndex value="65535"/>
+            <!-- FeatureCount=1 -->
+            <FeatureIndex index="0" value="0"/>
+          </DefaultLangSys>
+          <!-- LangSysCount=0 -->
+        </Script>
+      </ScriptRecord>
+    </ScriptList>
+    <FeatureList>
+      <!-- FeatureCount=1 -->
+      <FeatureRecord index="0">
+        <FeatureTag value="ss01"/>
+        <Feature>
+          <FeatureParamsStylisticSet>
+            <Version value="0"/>
+            <UINameID value="256"/>
+          </FeatureParamsStylisticSet>
+          <!-- LookupCount=1 -->
+          <LookupListIndex index="0" value="0"/>
+        </Feature>
+      </FeatureRecord>
+    </FeatureList>
+    <LookupList>
+      <!-- LookupCount=1 -->
+      <Lookup index="0">
+        <!-- LookupType=1 -->
+        <LookupFlag value="0"/>
+        <!-- SubTableCount=1 -->
+        <SingleSubst index="0">
+          <Substitution in="A" out="B"/>
+        </SingleSubst>
+      </Lookup>
+    </LookupList>
+  </GSUB>
+
+</ttFont>