Which is the logic and the order in kerning tables?
Let's make a hypothesis. I intend to create three different kerning tables inside the same Lookup, the first one for the letters (pairs as `AV`, `To`, `Fr` etc.), the second one for the punctuation (pairs as `W.` `T-` `F,` etc), the third one for the numbers. Should they be placed in a predefined order?
My problem is that if I create a `'kern' Horizontal Kernin lookup 1` and then two subtables, i.e. `'kern' Horizontal Kerning lookup 1 kerning class 1` and then `'kern' Horizontal Kerning lookup 1 kerning class 2`, only the first is applied. If it is reversed, same thing. The first one is applied, the second one ignored.
Have I to create different lookups (and not different subtables in the same lookup)?
Or there is a conflict if in the first subtable I have `WA` and in the second `W.' ? But are they summative?
Now I ask: what's wrong in my procedure? How can the problem be solved, perhaps keeping the various subtables distinct?