[Haskell-beginners] How to show a record

[martin]

Right, but this is merely a coincidence.

What I wanted is a way to show a value of a record, where all fields are instances of Show.

Haskell itself is able to do this (and it even figures out the accessors, which I am not even asking for).




Am 08/16/2014 12:39 PM, schrieb Roman Czyborra:
> Your particular types do not require your annoying repetition beyond
> [ show . pType, accepts, produces, workarea] with 1st show = (:[])
> 
> 
> 
> On Sat, Aug 16, 2014 at 10:45 AM, martin <martin.drautzburg at web.de <mailto:martin.drautzburg at web.de>> wrote:
> 
>     Hello all,
> 
>     I have a record type like this
> 
>             data Payload = Pl {
>                         pType    :: Char,
>                         accepts  :: String,
>                         produces :: String,
>                         workarea :: String} deriving (Eq)
> 
>     an I want to write my own show function. I ended up with somethink like this
> 
>             show pl = concatMap ( $ pl) [show . pType, show . accepts, show . produces, show . workarea]
> 
>     That repetition of "show ." annoys me, but of course without it the elements of that list would have different types. Is
>     there a way around it and how does haskell itself manage to show records?
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