Subject: Re: How much use of CLOS?
From: Erik Naggum <>
Date: 17 Oct 2002 03:59:01 +0000
Newsgroups: comp.lang.lisp
Message-ID: <>

* Peter Seibel
| Or is it just that you *start* with generic functions and then defclass
| the classes that you end up needing?

  In my view and experience, the best OO design focuses on what you want to
  do, and the classes fall naturally out of the design.  If you start with
  the classes, the apparently strong desire to design the intrinsically
  perfect class hierarchy can ruin the entire project.  Encapsulation and
  methods are two orthogonal dimensions that are extremely hard to get
  right at the same time before you have some experience with how the
  design works.  That CLOS does not force you to encapsulate the methods
  with the types is a major aspect to my ability to "think design" directly
  in CLOS.  After the design has been worked out in this way, it can be
  documented and discussed and revised.  Some would call this prototyping,
  but that appears to me to be an unhealthy state of mind, the intent to
  throw it away is too clear.

Erik Naggum, Oslo, Norway

Act from reason, and failure makes you rethink and study harder.
Act from faith, and failure makes you blame someone and push harder.