I’ve slightly removed the OpenType layout features, so it now only contains a calt feature which takes care of first and last letters of a word. I haven’t fully tested it, so let us know your results.
This is the new script; makes changes as you like:
script latn {
feature ContextualAlternates;
}
class @hightail [b o q v w b.high o.high q.high v.high w.high b.init o.init q.init v.init w.init];
class @lowercase [a b c d e f g h i j k l m n o p q r s t u v w x y z];
class @lowercasehigh [a.high b.high c.high d.high e.high f.high g.high h.high i.high j.high k.high l.high m.high n.high o.high p.high q.high r.high s.high t.high u.high v.high w.high x.high y.high z.high];
class @lowercaseinit [a.init b.init c.init d.init e.init f.init g.init h.init i.init j.init k.init l.init m.init n.init o.init p.init q.init r.init s.init t.init u.init v.init w.init x.init y.init z.init];
class @lowercasefina [a.fina b.fina c.fina d.fina e.fina f.fina g.fina h.fina i.fina j.fina k.fina l.fina m.fina n.fina o.fina p.fina q.fina r.fina s.fina t.fina u.fina v.fina w.fina x.fina y.fina z.fina];
class @lowercase_all [A B C D E F G H I J K L M N O P Q R S T U V W X Y Z a b c d e f g h i j k l m n o p q r s t u v w x y z a.high b.high c.high d.high e.high f.high g.high h.high i.high j.high k.high l.high m.high n.high o.high p.high q.high r.high s.high t.high u.high v.high w.high x.high y.high z.high a.init b.init c.init d.init e.init f.init g.init h.init i.init j.init k.init l.init m.init n.init o.init p.init q.init r.init s.init t.init u.init v.init w.init x.init y.init z.init a.fina b.fina c.fina d.fina e.fina f.fina g.fina h.fina i.fina j.fina k.fina l.fina m.fina n.fina o.fina p.fina q.fina r.fina s.fina t.fina u.fina v.fina w.fina x.fina y.fina z.fina];
feature ContextualAlternates calt {
lookup ChainingContextInit;
lookup ChainingContextFina;
lookup ChainingContextBetween;
lookup ChainingContextHighTail;
}
lookup ChainingContextBetween {
context (@lowercase_all) @lowercaseinit (@lowercase_all);
sub 0 SingleSubstitutionInitToNormal;
}
lookup ChainingContextFina {
context (@lowercase_all) @lowercase;
sub 0 SingleSubstitutionFina;
}
lookup ChainingContextHighTail {
context (@hightail) @lowercase;
sub 0 SingleSubstitutionHighTail;
}
lookup ChainingContextInit {
context @lowercase (@lowercase);
sub 0 SingleSubstitutionInit;
}
lookup SingleSubstitutionFina {
sub @lowercase -> @lowercasefina;
}
lookup SingleSubstitutionHighTail {
sub @lowercase -> @lowercasehigh;
}
lookup SingleSubstitutionInit {
sub @lowercase -> @lowercaseinit;
}
lookup SingleSubstitutionInitToNormal {
sub @lowercaseinit -> @lowercase;
}