Trifecta is best used via the parsers library, which is fairly well documented. This also (in theory) allows you to switch which parser you use between trifecta

Trifecta is best used via the parsers library, which is fairly well documented. This also (in theory) allows you to switch which parser you use between trifecta, parsec, attoparsec and even ReadP. I say in theory because the the semantics of these libraries differ.