There are lots of great libraries, like repa, servant, megaparsec, gloss, yampa… as well as bindings to lots of standard stuff. I consider parsing to be one of Haskell’s killer strengths and I would definitely use it to write a compiler.

There is also some popular user facing software like Pandoc, written in Haskell. And companies using it internally.

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epolanski 7 days ago | parent [-]

The only non irrelevant compiler ever written in Haskell is for another borderline dead project: Elm.

	▲	gylterud 7 days ago \| parent [-]
		What are you on about? The Agda compiler, Pugs, Cryptol, Idris, Copilot (not that copilot you are thinking of), GHC, PureScript, Elm… These might not be mainstream, but are (or were for Pugs, but the others are current) important within their niche.