# OpenType Feature File specification, section 5.d, example 1.
# http://www.adobe.com/devnet/opentype/afdko/topic_feature_file_syntax.html

feature F1 {
  substitute [one one.oldstyle] [slash fraction] [two two.oldstyle] by onehalf;
} F1;

# Since the OpenType specification does not allow ligature substitutions
# to be specified on target sequences that contain glyph classes, the
# implementation software will enumerate all specific glyph sequences
# if glyph classes are detected in <glyph sequence>.  Thus, the above
# example produces an identical representation in the font as if all
# the sequences were manually enumerated by the font editor:
feature F2 {
  substitute one          slash    two          by onehalf;
  substitute one.oldstyle slash    two          by onehalf;
  substitute one          fraction two          by onehalf;
  substitute one.oldstyle fraction two          by onehalf;
  substitute one          slash    two.oldstyle by onehalf;
  substitute one.oldstyle slash    two.oldstyle by onehalf;
  substitute one          fraction two.oldstyle by onehalf;
  substitute one.oldstyle fraction two.oldstyle by onehalf;
} F2;

# In the resulting OpenType GSUB table (spec5d1.ttx),
# we expect to see only one single lookup.