A simple an basic calculator built with Spec

Hi,
I wanted to share with those you could be interested a project I did to learn a little about Spec in Pharo 3.
It's a simple and very basic calculator. There code is all commented and I even include a little tutorial on how I build the UI. There are a number of issues however that I have to figure out being the most important a way to get the text displayed to be right-aligned. Also error handling and other...my point was just to focus on Spec.

If you are interested you can get it here:

MCHttpRepository
    location: 'http://ss3.gemstone.com/ss/Specalc'
    user: ''
    password: ''

and then Calculator new openWithSpec.
best regards
Nacho