Re: [Haskell-beginners] coding style: instead of let, return?

Good points, thank you. f Le 2013-07-13 16:29, Kim-Ee Yeoh a écrit :

On Sat, Jul 13, 2013 at 1:56 PM, Obscaenvs mailto:obscaenvs@gmail.com> wrote:

` let p1 <- mkName "p1" a <- newName "a" ` , we use ` p1 <- return $ mkName "p1" a <- newName "a" `.

The first case should start "let p1 = mkName ...".

The reason to avoid the second case is to avoid unnecessary function applications. Predicating on a bona fide monad (can't be too careful these days), the second is equivalent to the first because of the unit law.

(This being the beginners list, I should point out that it's pretty important to learn how to desugar do notation in one's head. Normally, reading lots of haskell code is enough to pick up that skill subconsciously.)

You might try re-asking the question on cafe if you're really interested in surveying this.

Personally, I'd start asking questions about code provenance when I see the second case.

-- Kim-Ee

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