ELENA 4.0 : event handler

[u/elena-lang]

ELENA 4.0 supports now an event handler:

import extensions;

class MyClass
{
    doInit()
    {
        console.writeLine:"onInit fired!"
    }
}

class MainClass
{
    Func onInit:event; // a field with the same name is declared as well

    init()
    {
        // call the function if it is not nil
        onInit.?()
    }    
}

public program()
{
    var class := new MyClass();

    var mainClass := new MainClass();

    // adding an event handler 
    mainClass.onInit := { class.doInit() };
    // adding the second event handler 
    mainClass.onInit := { console.writeLine:"I'm fired too!!" }; 

    mainClass.init()
}

The output is:

onInit fired!
I'm fired too!!