Scala: pre-initialize val while extending a class

Question

How do I pre-initialize a val and extend a class in Scala? e.g.: ``` object Start { def main(args: Array[String]): Unit = { new T() new T2() //T3? } } class T extends{val z = 10} with X with Y class T2 extends X with Y {val z=10} //class T3 extends{val z = 10} ??? Z with X with Y //???? class Z trait X { val z :Int } trait Y { this :X => println("Test: "+z) } ```

Accepted Answer

Use:

```
class T3 extends {val z = 10} with Z with X with Y
```

Scala Language Specification 2.9, 5.1.6:

```
EarlyDefs ::= ‘{’ [EarlyDef {semi EarlyDef}] ‘}’ ‘with’
```

So an early definition always has to be followed by a `with`

Scala: pre-initialize val while extending a class

Solution

Problem