[Haskell-cafe] Layer on a layer of record syntax in the type synonym?

[Daniel Trstenjak]

Hi Christopher,

On Fri, Dec 21, 2012 at 04:36:04AM -0900, Christopher Howard wrote:
> Using a simple type I gave earlier from my monadic type question...
> 
> code:
> --------
> data Socket3 a b c = Socket3 a b c
>   deriving (Show)
> --------
> 
> Is it possible somehow to layer on record syntax onto a synonym of the type?
> 
> The idea would be something like this...
> 
> code:
> --------
> type SpaceShip =
>   Socket3 { engine :: Last Engine
>           , hull :: Last Hull
>           , guns :: [Guns]
>           }
> --------
> 
> ...purely for the convenience. But this doesn't seem to work with "type"
> as it assumes you are referring to already made constructors, and
> evidently "newtype" only allows use of a single record. I could wrap it
> in a normal "data" declaration but that would add an extra layer of
> complexity I think.

I don't know in which context you would like to use the SpaceShip type,
but the solution using the very generic Socket3 might bite you later,
because you don't have a concrete type for your SpaceShip and can't 
identify it.

Why having a Socket3 in the first place, what's the point of it?



> 
> -- 
> frigidcode.com
> 



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