Compose and andThen methods

Question

I\'m following the tutorial Pattern matching & functional composition on Scala compose and andThen methods. There\'s such an example:

Answer 1

I believe the tutorial was written for an earlier version of Scala (probably 2.7.7 or earlier). There have been some changes in the compiler since then, namely, extensions to the type system, which now cause the type inferencing to fail on the:

addUhum(_).compose(addAhem(_))

The lifting to a function still works with that syntax if you just write:

addUhum(_)