Will using Scala in a more functional way (scalaz) incur a performance/maintainability penalty?

Question

I\'m currently working on a small project (< 10k loc) which is mainly pure but relies on mutable optimizations mainly based on iterators and some data-structure reuse for

Answer 1

Regarding Question One:

There will be some overhead by wrapping your computations into monads, applicatives, functors and other functional vodoo. But so does wrapping your computations into procedures, methods, objects.

The question's core is, how small the computation has to be, so that the wrapping starts to be noticeable. That's something noone will be to tell you without knowing some details of your project. However due to Scala's hybrid nature you don't have to go monads all the way down. It's quite possible to use the scalaz-like style for the higher-level compositions of your computations and use locally-contained mutable state where performance requires it.

Regarding Question Two:

Since I have no clue of the nature of your type signatures, if scalaz will help you by generalizing computations or if you will have to type your way around Scala's limited support for partial type constructor application.

If your type signatures go out of hand, I suggest that you try to declare type alias in a package object and use these.