This is an "Orphan" page. Its core content has not been shared: what you see below is a loose collection of pages and page snippets that mention this page, as well as snippets of this page that were quoted elsewhere.
Each class and each function add a concept to your language. Every time you create one - either from primitive statements or from other concepts you've already defined - you make your language more expressive. You rise it's level of abstraction.