Intermediate changes

commit_hash:c52dc7996a60242b5397523a3f8dada166c4c7c5

1 files changed, 17 insertions, 0 deletions

diff --git a/contrib/python/fonttools/fontTools/otlLib/builder.py b/contrib/python/fonttools/fontTools/otlLib/builder.py
index 8fc685683a..b944ea8c26 100644
--- a/contrib/python/fonttools/fontTools/otlLib/builder.py
+++ b/contrib/python/fonttools/fontTools/otlLib/builder.py
@@ -1,4 +1,5 @@
 from collections import namedtuple, OrderedDict
+import itertools
 import os
 from fontTools.misc.fixedTools import fixedToFloat
 from fontTools.misc.roundTools import otRound
@@ -798,6 +799,22 @@ class ChainContextSubstBuilder(ChainContextualBuilder):
                     res = sub
         return res
 
+    def find_chainable_ligature_subst(self, glyphs, replacement):
+        """Helper for add_ligature_subst_chained_()"""
+        res = None
+        for rule in self.rules[::-1]:
+            if rule.is_subtable_break:
+                return res
+            for sub in rule.lookups:
+                if not isinstance(sub, LigatureSubstBuilder):
+                    continue
+                if all(
+                    sub.ligatures.get(seq, replacement) == replacement
+                    for seq in itertools.product(*glyphs)
+                ):
+                    res = sub
+        return res
+
 
 class LigatureSubstBuilder(LookupBuilder):
     """Builds a Ligature Substitution (GSUB4) lookup.