def readFeatureFile(font, text, prepend=True):
 writer = FilterFeatureWriter(set(font.keys()))
 if prepend:
  text += font.features.text
 else:
  text = (font.features.text + text)
 parser.parseFeatures(writer, text)
 font.features.text = writer.write()

def readFeatureFile ( font , text , prepend = True ) : writer = FilterFeatureWriter ( set ( font . keys ( ) ) ) if prepend : text += font . features . text else : text = ( font . features . text + text ) parser . parseFeatures ( writer , text ) font . features . text = writer . write ( )
incorporate valid definitions from feature text into font .