This article is more about taking an existing type-checking system (http://www.sbcl.org/manual/#Handling-of-Types http://www.sbcl.org/manual/#Handling-of-Types)

This article is more about taking an existing type-checking system (http://www.sbcl.org/manual/#Handling-of-Types http://www.sbcl.org/manual/#Handling-of-Types) and adding some syntactic sugar so you can declare the types inline, similar to other languages, instead of separately.