Three letters and two ligatures

Glyphs
1

Hello.

I Googled and searched the forum for two hours, but I still couldn’t find it. GPT chat tries to help, but constantly writes different things :slight_smile:

Situation. There are ligatures D_O.liga and O_O.liga. Everything is fine, everything is being replaced.
But in a situation with the sequence of letters DOO, only the ligature O_O.liga should work. I think this is a simple situation, but… how to do it?

The Learn section has great lessons like Features, part 3: advanced contextual alternates | Glyphs. But this situation does not exist.

GPT chat writes something like:

feature calt {
sub D O by D_O.liga;
sub O O’ @DOOContext by O_O.liga;
} calt;

It’s as if there is a team that, in a DOO situation, changes only the second pair of letters to the ligature O_O.liga, without applying D_O.liga to the first pair.

Thank you.

2

From the OpenType Cookbook

What if we have a short context that you want to match, but a longer context that contains the short context? For example, say we want to change the r in words but not in words!. To do that we can specify an exception to the contextual rule. For example:

ignore sub w o r' d s exclam;
sub w o r' d s by r.alt;

The ignore keyword followed by a backtrack (optional), target and lookahead (optional) creates the exception.

1 Like
3

I admit, I still haven’t figured out how to do this.
Last thing I tried:

ignore sub D' O O;
sub D' O' O by D_O.liga;

Apparently I don’t understand how this works in my case.
But I realized that it works through "ignore’. And on the forum I found a piece of code that I was able to change for myself:

lookup OOliga {
    sub O O by O_O.liga;
} OOliga;

lookup DOliga {
    ignore sub D' O_O.liga;
    sub D' O' by D_O.liga;
} DOliga;

(At the same time, I had to remove the conflicting teams from the “liga”)

It works. But it seems to me that you were talking about an even simpler solution.

Thank you for your help!

4

No Ignore needed. Make one lookup that substitutes the OO and one that does the DO.

1 Like
5

Yes!
The main thing is that the OO is first, and then the DO.
Thank you!

lookup OOliga {
    sub O O by O_O.liga;
} OOliga;

lookup DOliga {
    sub D O by D_O.liga;
} DOliga;