Hi @andreaferretti

Thanks for writing this! This document is a nice introduction to Factor!

However, the name of some words have been modified in the latest version of Factor (at last as it is today in Github).
For instance, [a,b] is now [a..b].

I'll be learning Factor and will probably use it later to build some tools. If it makes sense to update the docs at this point, let me know and I would probably contribute updates while I have time to do it.