[Hs-Generics] Regular problem

[lists at snowlion.nl]

Hi Pedro,

Thanks! Works excellent.

Kind regards,

Maarten


On 01/18/2011 08:30 AM, José Pedro Magalhães wrote:
> Hi Maarten,
>
> I think I fixed it; please try 
> http://hackage.haskell.org/package/regular-0.3.1
>
>
> Cheers,
> Pedro
>
> 2011/1/17 José Pedro Magalhães <jpm at cs.uu.nl <mailto:jpm at cs.uu.nl>>
>
>     Hi Maarten,
>
>     This looks like a bug to me, thanks for reporting. I will fix it soon.
>
>
>     Cheers,
>     Pedro
>
>     On Mon, Jan 17, 2011 at 17:08, lists at snowlion.nl
>     <mailto:lists at snowlion.nl> <lists at snowlion.nl
>     <mailto:lists at snowlion.nl>> wrote:
>
>
>         Hi all,
>
>         /(I think something went wrong with my previous email, so if
>         this is sent twice, I apologize)
>         /
>         Why do self referential structure omit the selector in record
>         entries referencing themselves when converting to the regular
>         data structure?
>
>         For instance, when splicing the following data structure:
>
>         data P = V {v::String} | II {i::Integer} | P { p::P }
>           deriving Show
>
>         $(deriveAll ''P "PFP")
>         type instance PF P = PFP
>
>         It generates the following code:
>
>                 ...generics at haskell.org <mailto:generics at haskell.org>
>                 data P_P_ =
>                 ...
>                 instance Constructor P_P_ where
>                     { conName _ = "P"
>                       conIsRecord _ = True }
>                 ...
>                 data P_P_p_ =
>                 instance Selector P_V_v_ where
>                     { selName _ = "v" }
>                 ...
>                 instance Selector P_P_p_ where
>                     { selName _ = "p" }
>                 type PFP = :+: (C P_V_ (S P_V_v_ (K String))) (:+: (C
>         P_II_ (S P_II_i_ (K Integer))) (C P_P_ I))
>                 instance Regular P where
>                     {         ...generics at haskell.org
>         <mailto:generics at haskell.org>
>                         from II f0 = R (L (C (S (K f0))))
>                         from P f0 = R (R (C (I f0)))
>                         ...
>                         to R L C S K f0 = II f0
>                         to R R C I f0 = P f0 }
>
>         Why is the selector name in case of a self referencing record
>         omitted? I would have expected something like this:
>
>                 type PFP = :+: (C P_V_ (S P_V_v_ (K String))) (:+: (C
>         P_II_ (S P_II_i_ (K Integer))) (C P_P_ (S P_P_p_ I)))
>
>         and likewise:
>
>                         from II f0 = R (L (C (S (K f0))))
>                         from P f0 = R (R (C (S (I f0))))
>                         ...
>                         to R L C S K f0 = II f0
>                         to R R C S I f0 = P f0 }
>
>         This gives problems when parsing these kind of structure, or
>         am I missing something?
>
>         kind regards,
>
>         Maarten
>
>
>
>
>
>         _______________________________________________
>         Generics mailing list
>         Generics at haskell.org <mailto:Generics at haskell.org>
>         http://www.haskell.org/mailman/listinfo/generics
>
>
>

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://www.haskell.org/pipermail/generics/attachments/20110118/422cb029/attachment.htm>