Robert Fischer published an article titled “Scala is Not a Functional Programming Language”
In response Martin Odersky argues that Scala can be characterized as postfunctional:
[…] if you look at the features Scala provides, it is substantially a functional language, but on the surface it does not always look like one, and it does not force you to adopt the functional style.
In fact, great care has been spent in the Scala design to make functional constructs, imperative constructs, and objects all play well together.