John Hughes wrote:
Lennart Augustsson wrote:
On the subject of type signatures, I don't want to make them mandatory, but I think they should be strongly encouraged. I don't buy the argument that they make refactoring programs that much harder. It's still very easy to do, the type checker will tell you exactly where. :)
It can still be in a LOT of places--far too many for comfort. I'm not making this up--I've experienced severe problems in practice caused by this very point. It depends what kind of code you're working with, of course. I'm not saying type signatures are ALWAYS a problem for refactoring, just that they sometimes are--and that it makes sense to leave it up the programmer whether or not to include them.
So what if it's in a lot of places? The compiler tells you where to change. Each change takes a few seconds. Even with hundreds of changes you'd probably be done in under half an hour. Of course, you'd like a tool to do these kind of changes. All that said, I think not being able to give a name to a context is a real weakness in Haskell. It's one of the few things that cannot be named, and being able to do so would help refactoring and modularity. -- Lennart