Personally I prefer Haskell because it's pure. Here's some good book: http://learnyouahaskell.com/ http://learnyouahaskell.com/ Scala is just Java+FP, so I use

Personally I prefer Haskell because it's pure. Here's some good book: http://learnyouahaskell.com/ http://learnyouahaskell.com/ Scala is just Java+FP, so I use it as a replacement for Java development.