Understanding methods Vs functions in scala

Question

I am learning the difference between methods and functions. I am following this link

http://jim-mcbeath.blogspot.co.uk/2009/05/scala-functions-vs-methods.html

The article says if you compile the following code:

class test {
def m1(x:Int) = x+3
val f1 = (x:Int) => x+3
}

We should get two files 1. test.class 2. test$$anonfun$1.class

But I do not get it. Secondly the example says if we execute the following command in REPL, we will get the below

scala> val f1 = (x:Int) => x+3
f1: (Int) => Int = <function>

But I get only this

scala> val f1 = (x:Int) => x+3
f1: Int => Int = $$Lambda$1549/1290654769@6d5254f3

Is it because we are using a different version? Please help.

Yes, earlier versions of Scala (and REPL) will produce the <function1> representation of the result. — jwvh
– jwvh, Commented Jul 13, 2017 at 16:45
You should never rely on implementation details like this. For example, for obvious reasons, Scala.js will generate ecactly zero class files, always. — Jörg W Mittag
– Jörg W Mittag, Commented Jul 19, 2017 at 18:56

Seth Tisue · Accepted Answer · 2017-07-13 20:23:22Z

2

Scala 2.11 and earlier versions behave as shown in the blog post.

The behavior changed in Scala 2.12. Scala now uses the lambda support that was added to version 8 of the JVM, so it doesn't need to emit the extra .class file. As a result, the .jar files produced by 2.12 are usually a lot smaller.

As a side effect of this, Scala can't override toString anymore, so you see the standard JVM toString output for lambdas.

answered Jul 13, 2017 at 20:23

Seth Tisue

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