I agree. I'm not a great fan of Data, but I use it for various kinds
of serializations.
If a library doesn't support data, well that just means I'll try to
avoid that library.
-- Lennart
On Sun, Apr 19, 2009 at 4:39 PM, Sterling Clover
Am I to take it that you will not be providing Data instances because you find them "unhaskellish"? The time package is a core part of Haskell functionality, and those Data instances are sorely missed by a wide range of libraries. As the maintainer of a key part of the Haskell ecosystem, I think you are obligated to take into account not only what you find to be the "good bits," but also to provide instances such as Data that, even if you find them "unhaskellish" allow the library to better integrate into the Haskell package ecosystem as it now stands. Furthermore, if such instances are not provided, they will be created with standalone deriving. The instances created by standalone deriving, unlike instances which can be partially hand-written, will provide even less in the way of preservation of the abstract nature of certain data types. In the end, you may only be cutting off your nose to spite your face.
Cheers, Sterl.
On Apr 18, 2009, at 8:26 PM, Ashley Yakeley wrote:
Jeremy Shaw wrote:
At Fri, 17 Apr 2009 11:55:51 -0700, Ashley Yakeley wrote:
Instances of Typeable have been requested for various types. I'll add these for 1.1.3.
Sweet! Data as well? Happstack uses Data and Typeable for serialization. It would be nice to be able to use Data.Time instead of System.Time.
I'm not sure. I find the whole SYB approach unhaskellish, as it treats values based on their internal structure rather than their types. But perhaps serialisation is a harmless use of the Data class.
Typeable is also rather unhaskellish. A haskellish approach would be to use type witnesses, but it requires open witness declarations as a language extension. So, Typeable it is.
-- Ashley Yakeley Seattle, WA _______________________________________________ Libraries mailing list Libraries@haskell.org http://www.haskell.org/mailman/listinfo/libraries
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