[dreamcompiler]

CLOS (as well as a lot of other things in Common Lisp, like the error system) depends on CLOS being present. This is why writing a competent CLOS compiler that can bootstrap itself is very difficult. But it's so worth it.

[varjag]

How so?

The canonical implementation (PCL) was written in pre-ANSI CL without CLOS. There's a number of things that are difficult there, but can't put my finger on any related to bootstrapping.

[dreamcompiler]

PCL is a perfect example of what I'm talking about. Search for the string "braid" in the sources.