Just a bugbear: naming things with a ' (prime, apostrophe) is a mathy Haskellism, and it's often a sign that no thought has been put into the name. Sometimes it works, if x' is a transformed version of x and the transform is obvious (like, it's the whole purpose of the function, and the function itself is well-named -- the way you used h' and v' in Update.turn is a good example of that).
Especially for awesome i-wanna-fork-it sample code like this, to be read by new users, the fewer haskellisms the better ... hence this PR!
Just a bugbear: naming things with a ' (prime, apostrophe) is a mathy Haskellism, and it's often a sign that no thought has been put into the name. Sometimes it works, if x' is a transformed version of x and the transform is obvious (like, it's the whole purpose of the function, and the function itself is well-named -- the way you used h' and v' in Update.turn is a good example of that).
Especially for awesome i-wanna-fork-it sample code like this, to be read by new users, the fewer haskellisms the better ... hence this PR!