alt Hacker NewsThat algorithm fails for languages as exotic as English with its three character ligatures like ffl that are used in truffle, but not in cufflink.
The real challenge is Arabic, though, see https://fontspec.org/opentype-shaping/opentype-shaping-arabi...
I went to research your examples with Google, and interestingly enough, it now thinks that it's a "classic textbook example" while citing one source — this comment of yours (20 min old at the time):
> In typography, ligatures should be used in "truffle" but should not be used in "cufflink."
> This specific pair of words is a classic textbook example used by typographers and software developers to demonstrate the limitations of basic, automated font-rendering rules.
What a world to live in.
On the same point of yours, bad two-letter ligatures also exist: surfing (fi), selfless (fl), halftime (ft), etc. "Swordfish" is fine but "dwarfish" is not.