Incidentally, we may be able to autodiscover .asd files by scanning the classpath, and suitably update asdf:*central-registry*.
We first need to agree on a convention to wedge the concept of Pathname into CLASSPATH. I now support your earlier proposal to keep the two separate, as it makes more sense. And I'd like to get the "jar:" part of my changes into the trunk, and tested for a bit before introducing another the next step. Right now, wildcards (and DIRECTORY) don't work inside JARs which would be the first step to autodiscovery.
With Java resources, one is always warned against using the classpath that way. Looking for a particular path is possible, but listing paths (or files) not. It might be safer to introduce an additional concept. This could be an explicit list of Java resource paths or a new kind of ASDF classpath.
Here is how Spring does auto-detection: http://static.springsource.org/spring/docs/2.5.x/reference/beans.html#beans-...
Here is more information from Sun on finding classes: http://java.sun.com/j2se/1.5.0/docs/tooldocs/findingclasses.html