Toward better syntax errors

[Simon Peyton Jones]

Thank Dan.  I'm keen on better error messages.

If you want to change Happy, though, you need talk to Simon Marlow.

Simon

| -----Original Message-----
| From: ghc-devs [mailto:ghc-devs-bounces at haskell.org] On Behalf Of Dan
| Aloni
| Sent: 07 April 2015 21:34
| To: ghc-devs at haskell.org
| Subject: Toward better syntax errors
| 
| Hello,
| 
| Forwarded here is a link to a blog post I authored about improving
| GHC's syntax errors:
| 
| http://blog.aloni.org/posts/toward-better-ghc-syntax-errors/
| 
| In fact, this came about after I started using Happy more extensively,
| and at one point thought that GHC could benefit too
| 
| The gist of it, is that it was relatively easy to reach an improvement
| such as follows (notice 'possible tokens' below):
| 
| 
| input:
| --
| test i = case i of 2
| main = return ()
| 
| 
| output:
| --
| example1.hs:2:1: parse error (possibly incorrect indentation or
| mismatched brackets), possible tokens: '|' '->'
| 
| 
| It spawned a more extensive discussion regarding type errors here:
| 
| https://www.reddit.com/r/haskell/comments/31m7pc/toward_better_ghc_syntax
| _errors/
| 
| Following to that, it was suggested that a further discussion in the GHC
| dev mailing list can continue about this direction (syntax errors,
| type errors and whatnot).
| 
| --
| Dan Aloni
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