Re: Is 78 characters still a good option? Was: [Haskell-cafe] breaking too long lines

On 25 Apr 2009, at 10:51, Daniel Fischer wrote:

Am Samstag 25 April 2009 08:48:16 schrieb Thomas Davie:

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On 24 Apr 2009, at 14:37, Loup Vaillant wrote:

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2009/4/23 Miguel Mitrofanov :

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On 23 Apr 2009, at 12:17, Thomas Davie wrote:

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Haskell is a very horizontal language, and to limit our horizontal space seems pretty weird.

+1. I sometimes use lines up to 200 characters long, when I feel they would be more readable.

200 sounds awfully long. Do you have any example?

Sure...

arrow :: forall (~>) b c d e. ( Arrow (~>), Show (d ~> e), Show (c ~> d), Show (b ~> c), Show b, Show c, Show d, Show e, Arbitrary (d ~> e), Arbitrary (c ~> d), Arbitrary (b ~> c), Arbitrary b, Arbitrary c, Arbitrary d, Arbitrary e, EqProp (b ~> e), EqProp (b ~> d), EqProp ((b,d) ~> c), EqProp ((b,d) ~> (c,d)), EqProp ((b,e) ~> (d,e)), EqProp ((b,d) ~> (c,e)), EqProp b, EqProp c, EqProp d, EqProp e) => b ~> (c,d,e) -> TestBatch

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.>

In all seriousness though, that one got broken, but I do find that I occasionally have lines around 100 characters that just look silly if I break them, this is a good example:

filterNonRoots (GCase e bs ) = filter ((/= e) <^(&&)^> (not . (`elem` bs)))

Not that I'd deny that it can sometimes be more readable to have longer lines*, but in this example, would

filterNonRoots (GCase e bs ) = filter ((/= e) <^(&&)^> (not . (`elem` bs)))

be any less readable in your opinion?

Yes – this particular line is mixed in with several other pattern matches, each of which has a similar form, laying it out on one line lets you see the similarities and differences, laying it out on two lines creates visual noise. Bob