Comments for Lane's Blog

Comment on The One Function per Typeclass Rule by Agnieszka

Agnieszka — Sun, 13 Jan 2013 09:45:49 +0000

I was thinking about that, and I ddceied to explicitly write out the if then else, because it showed use of mzero/return, rather than a sort of magical (to those who don’t quite understand its operation) guard operator. I guess it would be a good thing to mention, though.

Comment on Cats are Parasites by mrinesi

mrinesi — Sat, 29 Dec 2012 02:02:09 +0000

It could be argued that giving humans a false sense of reproductive success *is* a benefit for them, as it reduces some of the biological pressures for reproduction, and helps them decide whether or not to have offspring in a less unconscious way.

Insofar as the “benefit” of children is the sense of reproductive success, cats are a cheaper way of obtaining it, and insofar as the “benefit” is something else, cats reduce one of the subconscious component in the decision. Given the huge commitment that is having a baby, it seems like a mutually beneficial relationship.

Comment on The One Function per Typeclass Rule by Ivan Miljenovic

Ivan Miljenovic — Sat, 28 Apr 2012 23:22:57 +0000

Whilst this kind of rule sounds nice, it is over-simplistic.

Type-classes typically seem to serve two purposes:

* Define a general property of many types (Eq, Functor, Monad, etc.)

* Defining an API for using common types interchangeably (analogous to ML-style Functors if I understand them correctly).

This rule completely fails this second case: the whole point of the type-class is to *have* that large grouping of methods together. Admittedly this second usage of type-classes isn’t used as much in Haskell, but there are still cases.