the example char class given works, but the one I tried - listing
specific chars - didn't work with any combination of backslash escaping...

#[Thu Aug 17 16:02:09] rabbit$ darcs replace --token-chars "[selfrd\._]" self.r
 self.block_in_file amdlib/storage/tinystore.py

darcs failed:  Bad token spec:  [selfrd\._]
#[Thu Aug 17 16:02:28] rabbit$ darcs replace --token-chars "[a-zA-Z_0-9\-\.]" s
elf.r self.block_in_file amdlib/storage/tinystore.py
#[Thu Aug 17 16:02:57] rabbit$

Hi,

This message usually means that one of your tokens is not a token according to
your spec.  For example, self.block_in_file contains a ``b'', but ``b'' is not
allowed in a token in your spec.

I agree that the message is not comprehensible -- I'll fix that.

The following patch updated the status of issue245 to be resolved in the unstable branch:

* resolve issue245: more precise 'Bad token spec' error messages. 
I think this resolves issue371 as well.

You can view the patch details online here: 
http://darcs.net/cgi-bin/darcs.cgi/unstable/?c=annotate&p=20080502204426-2067a-2e3873100fbddebd953c7c1b90fd48cd0657eb3d.gz