Multi-Value Assignment Behavior in Scala

Question

When Scala evaluates the following multiple value assignment:

val a, b, c = UUID.randomUUID()

I expected a == b && b == c && c == a (A) or a == null && b == null && c == UUID (B)

However, the result is a != b && b != c && c != a (C), where each value is initialized to an individual UUID.

Why is this? Java behaves like (B). I believe that (C) is more convenient, however I have not been able to find an explanation in the language doc.

Answer 1

From the scala language reference section 4.1:

A value definition val p1, ..., pn = e is a shorthand for the sequence of value definitions val p1 = e; ...; val pn = e.

So your example is shorthand for:

val a = UUID.randomUUID()
val b = UUID.randomUUID()
val c = UUID.randomUUID()