In Glyphs, I can type the font RTL, but in Microsoft Word and in Affinity Photo (a PS alternative program), the font will only type LTR. The RTL kerning is maintained if I manually add each letter to the left of the previous one.
Thank you in advance. 
What version of Glyphs do you have?
Iām using the current trial version (at least, the one I downloaded 22 days ago). Iām making a script for a constructed language from the Latin base: am I doomed to use Hebrew as a base instead, to maintain the direction?
Only Arabic and Hebrew (and a few other scripts) unicodes can do RTL. Glyphs is not so picky and lets all scripts be viewed in RLT.
Okay, I was wondering about that. Thank you for your time.