# OpenType Feature File specification, section 6.h.ii:
# Specifying Contextual Positioning with explicit lookup references
# http://www.adobe.com/devnet/opentype/afdko/topic_feature_file_syntax.html

# As of December 2015, the Feature File spec gives a malformed example.
# TODO: Once https://github.com/adobe-type-tools/afdko/issues/88 is fixed,
# we should use the example from the spec. For now, we made up our own.

languagesystem DFLT dflt;

markClass [acute grave] <anchor 500 800> @TOP_MARKS;
markClass macron <anchor 500 820> @TOP_MARKS;
markClass [cedilla] <anchor 500 -5> @BOTTOM_MARKS;
@ALL_MARKS = [@TOP_MARKS @BOTTOM_MARKS];

lookup CNTXT_PAIR_POS {
    position T o -10;
    position T c -12;
} CNTXT_PAIR_POS;
 
lookup CNTXT_MARK_TO_BASE {
    position base [o c]
        <anchor 500 10> mark @TOP_MARKS
        <anchor 500 -10> mark @BOTTOM_MARKS;
} CNTXT_MARK_TO_BASE;

feature test {
    position
        T' lookup CNTXT_PAIR_POS
        [o c]'
        @ALL_MARKS' lookup CNTXT_MARK_TO_BASE;
} test;