Although the "hist" feature is not presently supported by any layout applications, I am putting it in all my new fonts, along with longs.
sub s by longs;
sub longs' f by s;
sub longs longs' by s;
sub f longs' by s;
ignore sub longs' @letter;
sub longs' by s;
This satisfies all the circumstances listed by Andrew West, except the Genesis abbreviation, of course.
I haven't developed codes for other languages.
It would be cool to be able to apply this feature to e-books, especially those written in the longs days.
nb. "@letter" is a class comprising all letters other than "s". The "ignore" command is a clever way to handle substitutions at the end of words.

