Re: [Haskell-cafe] Why is toRational a method of Real?

On Thu, 5 Aug 2010, Ivan Lazar Miljenovic wrote:

On 5 August 2010 10:15, Lennart Augustsson wrote:

...

You're right.  It's bad to have toRational in Real.  It's also bad to have Show and Eq as superclasses to Num.

I understand why it's bad to have Show as a superclass, but why Eq? Because it stops you from using functions as numbers, etc. ?

Yes, and on lazy computable reals (==) is not defined for numbers that are equal.