I think the specific case of ligatures isn't a failure in strings per se, but a failure in Unicode in that it includes them in the first place. What "fi".upper()

I think the specific case of ligatures isn't a failure in strings per se, but a failure in Unicode in that it includes them in the first place. What "fi".upper() (or whatever) should do is kind of ambiguous. The following doesn't really seem appropriate: "fi".upper().lower() #=> "fi" But obviously nor does "fi".upper() #=> "fi" In Turkish (which distinguishes between dotted and dotless 'i'), this issue exists already: "ı".upper().lower() #=> "i" This case couldn't (so far as I know) be fixed by any string library without breaking Unicode compatibility, so it seems slightly disingenuous to call it an issue with strings.