Re: [Haskell-beginners] Ord

On 2011-12-30 12:58, Brandon Allbery wrote:

2011/12/30 Stanisław Findeisen mailto:stf-list@eisenbits.com>

Could anyone please explain to me what is going on here?

You must, when declaring an instance of Ord, provide *either* a definition of (compare) or a definition of (<=). Both have default implementations defined, but in terms of each other; so if you don't provide either one in your instance declaration, you get an infinite loop when you try to use Ord methods (because (compare) invokes (<=), which invokes (compare) ...).

If you don't provide either one, then you get an infinite loop, but this is a runtime problem, i.e. the code will compile. Right? How to declare an instance of Ord? -- This e-mail address is invalid, see: http://people.eisenbits.com/~stf/public-email-note.html . OpenPGP: E3D9 C030 88F5 D254 434C 6683 17DD 22A0 8A3B 5CC0