Re: Poll: Error message spans
On Wed, Jan 6, 2010 at 3:35 AM, Ian Lynagh wrote: > > Hi all, > > Currently, when GHC reports an error it only gives a source position, > not a source span. For example, with this module: > > main = print (f (const 'x' 'x') 'y') > f xs y = xs ++ [y] > > you get an error starting: > > u.hs:1:18: > Couldn't match expected type `[a]' against inferred type `Char' > > There's a (probably little-known) flag -ferror-spans with which you get > this error instead: > > u.hs:1:18-30: > Couldn't match expected type `[a]' against inferred type `Char' > > i.e. rather than just giving the start column number 18, it gives you > the span 18-30 (the "const 'x' 'x'"). > > > Would you find the extra information useful, or just noise? > i.e. should we show error spans by default? > > > Thanks > Ian > > ___ > Glasgow-haskell-users mailing list > Glasgow-haskell-users@haskell.org > http://www.haskell.org/mailman/listinfo/glasgow-haskell-users > I certainly wouldn't find it distracting, and I think it could be quite useful in many cases. I vote for turning it on by default. Alex ___ Glasgow-haskell-users mailing list Glasgow-haskell-users@haskell.org http://www.haskell.org/mailman/listinfo/glasgow-haskell-users
RE: Associativity of ViewPatterns
Good point. I'll fix that, in HEAD at least. Simon | -Original Message- | From: glasgow-haskell-users-boun...@haskell.org [mailto:glasgow-haskell-users- | boun...@haskell.org] On Behalf Of Bas van Dijk | Sent: 06 January 2010 12:44 | To: glasgow-haskell-users@haskell.org | Subject: Associativity of ViewPatterns | | Hello, | | Why is the following a syntax error: | | f (view1 -> view2 -> pattern) = ... | | and the following isn't: | | f (view1 -> (view2 -> pattern)) = ... | | I would prefer the first version. | | regards, | | Bas | ___ | Glasgow-haskell-users mailing list | Glasgow-haskell-users@haskell.org | http://www.haskell.org/mailman/listinfo/glasgow-haskell-users ___ Glasgow-haskell-users mailing list Glasgow-haskell-users@haskell.org http://www.haskell.org/mailman/listinfo/glasgow-haskell-users
Associativity of ViewPatterns
Hello, Why is the following a syntax error: f (view1 -> view2 -> pattern) = ... and the following isn't: f (view1 -> (view2 -> pattern)) = ... I would prefer the first version. regards, Bas ___ Glasgow-haskell-users mailing list Glasgow-haskell-users@haskell.org http://www.haskell.org/mailman/listinfo/glasgow-haskell-users
Re: Poll: Error message spans
Hello Ian, Wednesday, January 6, 2010, 2:35:09 PM, you wrote: > Would you find the extra information useful, or just noise? > i.e. should we show error spans by default? i think it's useful in some cases, and don't add noticeable visual overhead in remaining ones -- Best regards, Bulatmailto:bulat.zigans...@gmail.com ___ Glasgow-haskell-users mailing list Glasgow-haskell-users@haskell.org http://www.haskell.org/mailman/listinfo/glasgow-haskell-users
Poll: Error message spans
Hi all, Currently, when GHC reports an error it only gives a source position, not a source span. For example, with this module: main = print (f (const 'x' 'x') 'y') f xs y = xs ++ [y] you get an error starting: u.hs:1:18: Couldn't match expected type `[a]' against inferred type `Char' There's a (probably little-known) flag -ferror-spans with which you get this error instead: u.hs:1:18-30: Couldn't match expected type `[a]' against inferred type `Char' i.e. rather than just giving the start column number 18, it gives you the span 18-30 (the "const 'x' 'x'"). Would you find the extra information useful, or just noise? i.e. should we show error spans by default? Thanks Ian ___ Glasgow-haskell-users mailing list Glasgow-haskell-users@haskell.org http://www.haskell.org/mailman/listinfo/glasgow-haskell-users
