Hi Some of these can be automatically derived by the Data.Derive tool. If you want any more, then submit a patch and they can all be derived. http://www-users.cs.york.ac.uk/~ndm/derive/ The derivations Set, Is, From, Has, LazySet all look useful. A bit more documentation on what each one does would also be handy, if anyone wants to write it! Thanks Neil On Nov 24, 2007 4:01 PM, Thomas Hartman 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.

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-- 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@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe

On 11/25/07, Thomas Hartman 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.

Have a look at [http://code.haskell.org/category], and the associated blog posts http://twan.home.fmf.nl/blog/haskell/overloading-functional-references.detai... (http://tinyurl.com/2ustba) and http://twan.home.fmf.nl/blog/haskell/References-Arrows-and-Categories.detail... (http://tinyurl.com/2v8het) which discuss "functional references" (similar to Luke's), and include Template Haskell code for deriving more flexible accessors from a record declaration. Also check out HList [http://homepages.cwi.nl/~ralf/HList/], which can do some interesting things, provided you're willing to abandon the built-in record system. Stuart