Hey there! I'm working on some lexicons for a project and was trying to use mlf, which I really like the look of!
Unfortunately I quickly ran into an issue because I need support for empty, open unions, like what standard.size uses for it's content field in it's document lexicon.
I also noticed that there's not a way to specify an open union with only one ref in it.
Maybe we coulduse _ as the type for an open union with no refs and string | _ as an open union with string variant?
This is now implemented.