[Haskell-cafe] Comments from OCaml Hacker Brian Hurt

Thu Jan 15 10:34:38 EST 2009

Hi folks,
Don Stewart noticed this blog post on Haskell by Brian Hurt, an OCaml
hacker:
http://enfranchisedmind.com/blog/2009/01/15/random-thoughts-on-haskell/
It's a great post, and I encourage people to read it. I'd like to
highlight one particular paragraph:
 One thing that does annoy me about Haskell- naming. Say you've
 noticed a common pattern, a lot of data structures are similar to
 the difference list I described above, in that they have an empty
 state and the ability to append things onto the end. Now, for
 various reasons, you want to give this pattern a name using on
 Haskell's tools for expressing common idioms as general patterns
 (type classes, in this case). What name do you give it? I'd be
 inclined to call it something like "Appendable". But no, Haskell
 calls this pattern a "Monoid". Yep, that's all a monoid is-
 something with an empty state and the ability to append things to
 the end. Well, it's a little more general than that, but not
 much. Simon Peyton Jones once commented that the biggest mistake
 Haskell made was to call them "monads" instead of "warm, fluffy
 things". Well, Haskell is exacerbating that mistake. Haskell
 developers, stop letting the category theorists name
 things. Please. I beg of you. 
I'd like to echo that sentiment!
He went on to add:
 If you?re not a category theorists, and you're learning (or thinking
 of learning) Haskell, don't get scared off by names like "monoid" or
 "functor". And ignore anyone who starts their explanation with
 references to category theory- you don't need to know category
 theory, and I don't think it helps.
I'd echo that one too.
-- John