Re: Maximum and Minimum monoids

On 28/12/2012, Edward Kmett <ekmett@gmail.com> wrote:

And they are already present in the semigroups package with those names and that Monoid.

Ah, sorry, missed the Monoid instance. On 28/12/2012, Gabriel Gonzalez <gabriel439@gmail.com> wrote:

Moreover, the entire Bounded constraint seems wrong in principle. There is no intuitive reason why some type should be bounded to be able to take a maximum of a set of elements. The Ord constraint should be sufficient to define a maximum.

No; the set may be empty.

I also don't think it is a good idea to have direct Monoid instances for Max and Min, because they behave weirdly on empty lists. Do you really think that "minimum [] :: Int" should be defined?

If we had the Bounded constraint, it wouldn't be.