Tony Morris

@djspiewak "You don’t have any way to abstract over sets of funcs" - not true, done via data types, but constraints live at use-site.

@markhibberd Then the constraints are scattered through your code. Also, there is less power there than in a trait with abstract functions.

@djspiewak It is painful to see code trapped, and un-useable because of a constraint that doesn't add laws and is not necessary for scenario

@markhibberd Trapped by what? A module where you don’twant the rest of it? That’s bad module design. Don’t do that. :-)

@djspiewak Fair enough. Your example last night fell into the trap. Didn't need Monad only Applicative, so a bunch of useful things excluded

@markhibberd I didn’t even need Applicative, just Functor. One lovely thing about modules is I could have said def M: Functor[M].

@djspiewak @markhibberd really? You had data1:M[List[Int]] and data2: M[List[Int]], how you go to M[Double] without Applicative?