[jefftk]

Converting "fi" into "fi" only requires a lookup table, though fonts can do some pretty fancy things: https://developer.apple.com/fonts/TrueType-Reference-Manual/...

Knowing that "Mr. Smith." is intra-sentence but "Me. Smith." is inter-sentence is well beyond what fonts can do, however.

[dubya]

I thought the rule was that ligatures shouldn't cross syllable boundaries. Like the fi in "fine" can be replaced but not the fi in "barfing", so it would need to be a bit more than a lookup table. Or maybe a dictionary-sized lookup table isn't a problem anymore.

[jefftk]

I see https://english.stackexchange.com/questions/50660/when-shoul... suggesting this, but I don't believe any fonts implement this.