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Comment by dkersten | Hacker News Reader

Are fst and snd the standard haskell functions? It doesn't seem worth saving a few characters for how awkward it makes it to read the code, but then again, if we can get used to car, cdr and so on, I guess its not bad. Though in the case of the tutorial, it should definitely state what fst and snd are.

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They are standard. There's also `first` and `second`, but they do something different:

    Prelude> :m + Control.Arrow 
    Prelude Control.Arrow> :t first
    first :: (Arrow a) => a b c -> a (b, d) (c, d)
    Prelude Control.Arrow> first (2 +) (1, 4)
    (3,4)

In this case the Arrow instance is just (->), the function type constructor, so you could read that strange type signature as `first :: (b -> c) -> ((b, d) -> (c, d))`. But I've said too much.

...if we can get used to car, cdr and so on, I guess its not bad.

Common Lisp (and MzScheme) users can use first (and second, and third...) and rest, and probably should do so when using simple lists.

My Lisp of choice is Clojure, which also uses first, second and rest.

Hey, I will explain fst and snd. In fact I go into them in some detail in later chapters, but I'll mention their use and why they're short at this step too!

Cool. Good work on the site anyway, I had a quick look at it and it seems like a nice and easy way to learn haskell.

Hey, cheers! I've updated the tutorial to explain fst, let, etc. hopefully it's a bit more friendly now.

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