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Re: Fixing optional arguments?
- To: Gregor Kiczales <Gregor.pa@Xerox.COM>, DCP@QUABBIN.SCRC.Symbolics.COM
- Subject: Re: Fixing optional arguments?
- From: David C. Plummer <DCP@QUABBIN.SCRC.Symbolics.COM>
- Date: Fri, 29 Aug 86 12:50 EDT
- Cc: Fahlman@C.CS.CMU.EDU, Common-Lisp@SU-AI.ARPA
- In-reply-to: <860828-111926-234@Xerox>
Date: 28 Aug 86 11:18 PDT
From: Gregor Kiczales <Gregor.pa@Xerox.COM>
From: David C. Plummer <DCP@QUABBIN.SCRC.Symbolics.COM>
Subject: Fixing optional arguments?
and somebody calls it with B or C being the value of unsupplied-... That
means I would have to put a prelude function in that looks roughly like
No you wouldn't have to put such a prelude. As soon as function call sees the
value of unsupplied-optional-argument it drops the rest of the arguments on
I guess that depends a lot on how your architecture does function
calling. Many machines currently do not look at the value of the
arguments, partly for historical reasons, partly for speed and perhaps
partly for ease of implementation. It would also have to be very
careful if some CL extension included the MultiLisp concept of futures.
In that case, you DON'T want to examine the data (or you have to do so
very carefully) for fear of forcing the contained computation to