Re: Poll: Error message spans
Additionally, tools based on the GHC API already have this information available and wouldn't be affected either way. -- Push the envelope. Watch it bend. ___ Glasgow-haskell-users mailing list Glasgow-haskell-users@haskell.org http://www.haskell.org/mailman/listinfo/glasgow-haskell-users
Re: Poll: Error message spans
On Mon, Jan 11, 2010 at 10:10:03AM +, Simon Marlow wrote: don't think I've ever wanted to know the endpoint of the expression to which an error message refers, Here's an example where it is useful (arguably due to a poor error message): http://hackage.haskell.org/trac/ghc/ticket/3746 Thanks Ian ___ Glasgow-haskell-users mailing list Glasgow-haskell-users@haskell.org http://www.haskell.org/mailman/listinfo/glasgow-haskell-users
Re: Poll: Error message spans
On 06/01/10 11:35, Ian Lynagh wrote: 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? I think we should point out that this will mean tools that interpret GHC error messages will need to be updated: e.g. Emacs/vim modes. Errors that span multiple lines look like this: Foo.hs:(1,0)-(10,33): ... though the exact format could be changed. I lean towards leaving it turned off. Visual tools that want to turn it on can do so, but using GHC from the command line with a text editor I don't think I've ever wanted to know the endpoint of the expression to which an error message refers, and there are downsides: breaking tools, and extra clutter in the error messages. Cheers, Simon ___ Glasgow-haskell-users mailing list Glasgow-haskell-users@haskell.org http://www.haskell.org/mailman/listinfo/glasgow-haskell-users
Re: Poll: Error message spans
On Wed, Jan 06, 2010 at 09:01:46PM -0800, Alexander Dunlap wrote: On Wed, Jan 6, 2010 at 3:35 AM, Ian Lynagh ig...@earth.li wrote: Would you find the extra information useful, or just noise? i.e. should we show error spans by default? 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. I agree. -Brent ___ Glasgow-haskell-users mailing list Glasgow-haskell-users@haskell.org http://www.haskell.org/mailman/listinfo/glasgow-haskell-users
Re: Poll: Error message spans
Would you find the extra information useful, or just noise? i.e. should we show error spans by default? 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. I agree. +1. It is a feature I have always found useful in other tools. (Although ghc does usually quote the entire literal source expression denoted by the span, so perhaps the info is slightly redundant.) Regards, Malcolm ___ 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
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
Re: Poll: Error message spans
On Wed, Jan 6, 2010 at 3:35 AM, Ian Lynagh ig...@earth.li 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
