How do you access an object instance in the second parameter of the Mootools fireEvent function?

I'm working through Implements: [Events, Options] in Mootools.

I would like to pass a class property to the function that is called when an event fires. I would have thought that I could do it using this but this is undefined.

I have commented the code below where my problem is. I have a feeling that this might be to do with binding so I will be having a look at that now. Thanks in advance for any help!

var Person = new Class({

    Implements: [Options, Events],

    initialize: function(options){
        this.setOptions(options);
    }

});

greet = function(name){
    log('Hello, I am ' + name);
}

var ryan = new Person({
    name: 'Ryan',
    onArrive: greet //add event 'arrive'
});
ryan.fireEvent('arrive', ryan.options.name); //ideally I would use this.options.name?

This code works but it just seems strange to use the object instance name instead of this in the last line.

When you fire the event this is your instance of ryan. To make it work just make the following changes

function greet(name){
    log('Hello, I am ' + this.options.name); //<-- use this here 
}

ryan.fireEvent('arrive');

but since greet now depends on the instance it would be better to include it in your class definition

var Person = new Class({

    Implements: [Options, Events],

    initialize: function(options){
        this.setOptions(options);
    },
    greet: function() { log('Hello, I am ' + this.options.name); //<-- use this here  }
});

and

var ryan = new Person({
    name: 'Ryan',
    onArrive: this.greet.bind(this)  //or a function() { /* log('Hello,... */}
});