[jimbokun]

> This is useful for compiler programmers

But that's incredibly powerful.

Now, stuff that would have to be implemented in the compiler to update the language, can now be written just as a "normal" program, that adds whole new features to your programming language.

For example, the entire object system in Common Lisp was implemented as macros.

Yes, most programming tasks don't require this kind of power. But it does mean programming in Lisp it's very very rare you are going to be stuck because your programming language doesn't implement some feature you need for the task at hand.

[lispm]

> For example, the entire object system in Common Lisp was implemented as macros.

It wasn't. The original Object System implementation of Common Lisp is has tree layers: at the bottom layer it is object-oriented (especially the Meta-Object Protocol), then there is a functional layer and on top there are macros for the convenience of the user.