How would I express a chained assignment in Scala?

Question

How would I express the following java code in scala?

a = b = c;

By the way, I\'m re-assigning variables (not declaring).

Answer 1

Using the fact that the left-hand-side of an assignment is syntactically a pattern. (See PatVarDef > PatDef > Pattern2 in SLS.)

a = b = 5

scala> val a@b = 5
a: Int = 5
b: Int = 5

x = y = z = new Object

scala> var x@(y@z) = new Object
x: java.lang.Object = java.lang.Object@205144
y: java.lang.Object = java.lang.Object@205144
z: java.lang.Object = java.lang.Object@205144

Note that the expression on the right-hand-site is evaluated only once.

Unfortunately, this syntax doesn't work for reassigning (so for x = y = value you still have to do x = value; y = x).

See also [scala-language] Chained assignment in Scala