intercepting undefined function errors

[Don Morrison <dfm@JASPER.PALLADIAN.COM>]

    Date: Wed, 5 Aug 87 14:32:41 EDT
    From: bromley@Think.COM

       Date: Wed, 5 Aug 87 12:34 EDT
       From: Jeffrey P. Golden <jpg@allegheny.scrc.symbolics.com>

       As you may know, MACSYMA has long had an "autoload" feature 
       ...

    ...

    If Lucid provided a reasonable way to give advice (as in Symbolics advise) you
    would use that instead of this rather ugly redefinition.

At release 2.10 Lucid does provide defadvice.  See chapter 14 (Miscellaneous
Programming Features) in the "User's Guide" for details.  It appears to work fine,
'though the documentation has a couple of typos regarding its syntax, at least in the
version I've got (Apollo revision 01): the syntax description for defadvice is
missing a pair of parens, and that for advice-continue an &rest.