Re: Remove Enum from Float and Double

If we truly believe that the instance is dangerous for users (and not merely for people who don't understand floating point arithmetic on computers), then we should add a deprecation pragma to the instance and discourage its use. But what would the deprecation message encourage instead, for users to write an explicit loop that tests against some lower/upper bound? It would have the same problem as enumFromTo. I think the issue here is really that floating point math on computers is hard to think about. On Tue, Jun 11, 2013 at 11:18 AM, harry wrote:

Johan Tibell writes:

...

I don't see much gain. It will break previously working code and the workaround to the breakage will likely be manually reimplementing enumFromTo in each instance.

I forgot the main point of my post :-)

The primary motivation for removing these instances is that they cause endless confusion for beginners, e.g.

http://stackoverflow.com/questions/13203471/the-math-behind-1-09999999999999... , http://stackoverflow.com/questions/9810002/floating-point-list-generator, http://stackoverflow.com/questions/7290438/haskell-ranges-and-floats,

http://stackoverflow.com/questions/10328435/how-to-solve-floating-point-numb... , and many more.

On the other hand, how much working code is there "correctly" using there instances?

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