for a monospace font I need to reaplace i e plus plus by plus_plus.liga.
In order to keep it a truly monospaced font, I have to add one space before or after the liga (which therefor has to have a negative sidebearing on one side).
Unfortunately writing the following seems to be not allowed:
sub plus plus by plus_plus.liga space;
I get: Invalid ligature rule replacement
What solution would be best?
(Yes, I have read https://forum.glyphsapp.com/t/coding-ligatures-in-monospaced-font/8595 already but still do not really get, where I would put that feature in particular. Especially with dozens of ligatures)