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Re: backquote
- To: ssmith@nrtc.northrop.com, donc@vaxa.isi.edu
- Subject: Re: backquote
- From: Robert W. Kerns <RWK@f.ila.dialnet.symbolics.com>
- Date: Fri, 11 Nov 88 19:08 EST
- Cc: common-lisp@sail.stanford.edu
- In-reply-to: The message of 10 Nov 88 19:46 EST from Stephen P. Smith <ssmith@ruffles.nrtc.northrop.com>
Date: Thu, 10 Nov 88 16:46:32 -0800
From: "Stephen P. Smith" <ssmith@ruffles.nrtc.northrop.com>
From your question about the CLtL reference on page 350: It was
also never clear to me without lots of experimentation what
such constructs as ,',@ should do either (or that they were
really allowed).
Well, ,',@X is basically nonsense, unless you KNOW that X is exactly
one element long. Otherwise you're passing the wrong number of
arguments to the QUOTE special form. If you thin kyou want ,',@, you
probably want ,@',X.
One way to look at ,@',X and ,',X is that these evaluate the X from the
OUTER backquote's context. Remember, the outer one is actually BUILDING
the inner one. The inner one being built is then "commafying" a quoted
list.