On 28/11/2006, at 11:28 AM, Ian Lynagh wrote:
On Mon, Nov 20, 2006 at 12:05:46PM +0000, Malcolm Wallace wrote:
Prompted by recent discussion on the Hat mailing list about the problems of type-defaulting, I have added two new proposals for this issue to the Haskell-prime wiki at:
http://hackage.haskell.org/trac/haskell-prime/wiki/Defaulting
I don't see a proposal to remove defaulting defaulting altogether on that page - has that been discussed already?
Am I the only one who puts an explicit type signature in whenever my compiler warns me that it is having to do some defaulting? And probably 99% of those would be unnecessary if (^)'s second argument was an Int, with a genericPower (or whatever) function providing the current type signature (analogous to, for example, (!!) and genericIndex).
Defaulting is one wart I would be glad to be rid of.
I would also be happy if it was removed. My main reasons are: 1) It makes teaching Haskell more difficult, because it is a special case mechanism. I would prefer consistency here. 2) It makes source-to-source program transformations more difficult, as found in Hat etc. 3) I have found it easy to avoid with the addition of type annotations. I don't write a lot of numeric code, so the benefits I personally get from defaulting have so far been minimal, and that has coloured my view. Others may find it more useful. Cheers, Bernie.