[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

nested backquotes

   Posted-Date: Wed, 16 Nov 88 11:54:30 PST
   Date: Wed, 16 Nov 88 11:54:30 PST
   From: Don Cohen <donc@vaxa.isi.edu>

   I agree that my model does not handle this case.
   I had a hard time seeing how your model does.
   The Greenwald explanation gives me a hint of how to
   interpret CLtL.  I think what I was missing was the
   idea that [,,x] would be interpreted by treating the
   inner comma as part of the form in the outer comma,
   e.g., [(comma (comma x))] => (list (comma x)).

   Just to test my new interpretation, does this look right?
   (setq x '(y z))
   ``(,@,@x) =>
   `(append [,@,@x] 'nil) =>
   `(append ,@x 'nil) =>
   (append [append] [,@x] ['nil] nil) =>
   (append (list 'append) x (list ''nil) nil)
   which evaluates to (APPEND Y Z 'NIL)