mekkablue, I appreciate your help, thanks. I did paste exactly that myself, above. And the menu which appears by following that instruction, going to ‘Edit’ - I included a screenshot of that menu above for clarity. There is no ‘Font Info’ on that menu.
However, I found another way. Which it also mentioned on that page but intermixed with that instruction to go to the Edit menu, which totally threw me off. So actually within the Features pane which you get to through the window that appears when you click the info button, there’s a + sign on the bottom, Can create a new feature and name it kern.
So, I have it working!
Also it gives this warning:
Since our lookup is feature code that gets injected into every instance at export time, the contextual kerning does not interpolate. But that is not much of a biggie, usually.
I don’t actually understand what that means, but seems I can’t see the changes until exported and used by Pages for example. Looking promising so far! (Is there any way to be able to see the changes from within Glyphs? Would be handy for getting the positioning right!)
Now I am just wondering how to deal with ligatures with this. Say I want:
pos A B’ 200 C;
But say AB is (/makes) a ligature. And I want to preserve that ligature. Do I type:
A_B’ 200 C;
A_B.liga’ 200 C;
A B’ 200 C;