[Hs-Generics] Regular problem

[José Pedro Magalhães]

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>

> 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 <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
>>         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
>>                 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
>>
>>
>>
>>
>>
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>>
>>
>
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