UnboxedTuples - mrsekut-p

UnboxedTuples

http://www.kotha.net/ghcguide_ja/7.6.2/primitives.html#unboxed-tuples

(# e_1, ..., e_n #)みたいなやつ

IOの実装とか覗くと見かける

code:hs

newtype IO a = IO (State# RealWorld -> (# State# RealWorld, a #))

https://ghc.gitlab.haskell.org/ghc/doc/users_guide/exts/primitives.html#glasgow-unboxed

https://ghc.gitlab.haskell.org/ghc/doc/users_guide/exts/primitives.html#primitives