[Haskell-cafe] Human-friendly compiler errors for GHC

[Arthur van Leeuwen]

On 13 jul 2008, at 15:36, Max Bolingbroke wrote:

[snip, patches towards friendlier error messages in GHC]

>> Then again, we don't do fuzzy matching, only completion
>> of partial identifiers and suggesting possible qualified
>> names and imports for unqualified ones.
>
> Agreed: doing fuzzy matching on >every< available identifier from all
> packages would truly suck. I would propose just looking for exact
> matches in non-imported modules for identifiers that are not in scope.

The approach taken by Helium (which doesn't quite do full Haskell''98  
yet)
is to not just do fuzzy matching, but to figure out if the identifiers  
that
were fuzzily matched also have the right type. For more info, read
Bastiaan Heeren's PhD Thesis: Top Quality Type Error Messages.
available at http://people.cs.uu.nl/bastiaan/phdthesis/

> Well, noone has actually said they think fuzzy matching would be
> useful yet, so I suspect this patch is dead on the vine :). I've filed
> a ticket with the code anyway
> (http://hackage.haskell.org/trac/ghc/ticket/2442) so at least it's
> available for others to look at.

More help is very much useful. However, there are different use cases
that imply different types of help and diffent types of searching.

With kind regards, Arthur van Leeuwen.

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