[Haskell-cafe] is there a more concise way to generate helper functions for a datatype built on records?

[Luke Palmer]

I think records are grungy, too.

I'm not sure what available options there are on Hackage, but here are
some of my attempted solutions:

http://luqui.org/blog/archives/2007/08/05/haskell-state-accessors-second-attempt-composability/

And here's the automatic derivation module I said I'd write in the post:

http://svn.luqui.org/svn/misc/luke/work/code/haskell/accessor/

It's all experimental, but it seems to do the trick pretty nicely.

Luke

On Nov 24, 2007 4:01 PM, Thomas Hartman <tphyahoo at gmail.com> wrote:
> I think I'm running into more or less the same issue discussed at
>
> http://bloggablea.wordpress.com/2007/04/24/haskell-records-considered-grungy/
>
> Just wondering if I missed anything, or if any of the ideas
> considering better records setter/getters have been implemented in the
> meantime.
>
> t.
>
>
> **************
>
> -- Is there any way to do the following more concisely?
> -- Seems like a lot of boilerplate
>
> data GameState = GameState { guesses :: Int, userHighScores ::
> UserHighScores, answer :: Maybe Int }
>   deriving Show
>
> -- State Helpers ---------------------------------------
> modGuesses f gSt  = _set_guesses ( (f . guesses) gSt) gSt
> modUserHighScores f gSt = _set_userHighScores ( (f . userHighScores) gSt) gSt
> modAnswer f gSt = _set_answer ( (f . answer) gSt) gSt
>
> _set_guesses new gSt   = gSt {guesses=new}
> _set_userHighScores new gSt = gSt { userHighScores=new }
> _set_answer new gSt = gSt { answer=new }
> _______________________________________________
> Haskell-Cafe mailing list
> Haskell-Cafe at haskell.org
> http://www.haskell.org/mailman/listinfo/haskell-cafe
>