Think of a programming language. It has some built-in data types, and it has so-called literals for each of those. The parser reads in some text and produces a

Think of a programming language. It has some built-in data types, and it has so-called literals for each of those. The parser reads in some text and produces a value of some kind. In Lisp, the program itself is really one large "code literal", which happens to be run by the language environment. But there are plenty of other things you can do with programs besides just running them, and generating them is one of those things. Lisp merely provides handy facilities for performing these manipulations.