[Haskell-cafe] looking for alex+happy examples that uses location annotated tokens and location information in err msgs

Mateusz Kowalczyk fuuzetsu at fuuzetsu.co.uk
Sun Mar 9 07:49:02 UTC 2014

On 08/03/14 21:47, Ömer Sinan Ağacan wrote:
> Does anyone have any example alex+happy programs that uses location
> location annotated tokens and location information of token while
> reporting parse errors?
> I already wrote lexer and my function type is something like:
>> runLexer :: String -> [(Token, AlexPosn)]
> where AlexPosn type contains location information. But I have no idea
> how can I use that in happy to parse and use location information in
> parse error messages. There are lots of examples in interwebs but as
> far as I can see none of them works on location-annotated tokens.
> Thanks..
> ---
> Ömer Sinan Ağacan
> http://osa1.net
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> Haskell-Cafe at haskell.org
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I believe GHC does this. See the compiler/parser directory of the GHC
repo. Perhaps it's not the most lightweight example but it's the only
readily available one that I can think of.

Mateusz K.

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