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Re: do-nothing macro generates nil nevertheless
- To: email@example.com
- Subject: Re: do-nothing macro generates nil nevertheless
- From: Erik Naggum <firstname.lastname@example.org>
- Date: 27 Feb 1995 21:13:16 UT
- Organization: Naggum Software; +47 2295 0313
- References: <email@example.com>, <firstname.lastname@example.org>, <email@example.com>
- Sender: firstname.lastname@example.org
| There should be a way to make a macro that can be as transparent as #+
| is when its symbol is not in *features*. That's what I should have
#+ as a reader function has very special provisions available, namely that
returning zero values "contributes nothing to the object being read".
(CLtL2 p 543). by the time you start to evaluate a macro, it is obviously
too late for a similar mechanism.
the compatibility note on page 543 also includes a note that MacLisp and
Interlisp had splicing macro characters that could splicing of arbitrarily
many values. I think I understand this, but maybe somebody can tell me why
was this capability removed from Common Lisp?
hmmm. what should reading (#.(values) #.(values 1) #.(values 1 2)) return?
gcl-1.1 says (NIL 1 1). CMUCL 17f says (1 1). WCL 2.2 says (1 1). CLISP
(version?) says (NIL 1 1).
miracle of miracles. look what the Net dragged in.