[Haskell-cafe] ANNOUNCE: Agata-0.2.0

Sebastiaan Visser sfvisser at cs.uu.nl
Tue Apr 20 09:13:47 EDT 2010


You can also derive (Co)Arbitrary instances automatically using the regular-extras package based on the Regular generic programming library.

The advantage of using a library like Regular is that you do not have to write any Template Haskell code. The library generates a nice algebraic generic view on your datatype that you can use to write your generic functions. The Regular library itself of course uses TH internally, but this is done once and all datatype generic functions can piggy bag on the same TH derivation. For example, look at Generics.Regular.Functions.Arbitrary, this module is really concise.

Nice work though!


On Apr 18, 2010, at 1:43 AM, Jonas Almström Duregård wrote:
> I'm pleased to announce Agata (Agata Generates Algebraic Types Automatically)!
> Avoiding excessive details, usage is best described by a small example:
> {-#LANGUAGE TemplateHaskell #-}
> import Test.QuickCheck
> import Test.AgataTH
> data X a b = X [Either a b] deriving Show
> data Y = Y deriving Show
> data Z = Z deriving Show
> $(agatath $ deriveall [''X,''Y,''Z])
> main = sample (arbitrary :: Gen (X Y Z))
> This code derives instances of Test.QuickCheck.Arbitrary for the data
> types X, Y and Z.
> http://hackage.haskell.org/package/Agata
> Regards Jonas

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