[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Extension to MAP
- To: David A. Moon <Moon@STONY-BROOK.SCRC.Symbolics.COM>
- Subject: Extension to MAP
- From: Robert W. Kerns <RWK@YUKON.SCRC.Symbolics.COM>
- Date: Sat, 21 Mar 87 04:47 EST
- Cc: VERACSD@A.ISI.EDU, common-lisp@SAIL.STANFORD.EDU, veracsd.rs@A.ISI.EDU
- In-reply-to: <870320170530.1.MOON@EUPHRATES.SCRC.Symbolics.COM>
Date: Fri, 20 Mar 87 17:05 EST
From: David A. Moon <Moon@STONY-BROOK.SCRC.Symbolics.COM>
Date: 20 Mar 1987 16:24-EST
I'd really like to see MAP take a sequence as its first
argument, and have the results be put into that sequence.
The first N elements of the sequence would be modified
where N is the min of the lengths of the argument sequences,
(including the sequence passed as the first arg).
This seems upward-compatible and easy to implement, and
would be extremely handy.
It sounds like a good idea, but what if the sequence is () ?
I'm not sure which objection you're making, so I'll clarify by
generalizing it twice.
1) Generalize this to "What if the sequence is shorter than the
number of times the mapped function would otherwise be called?"
2) Generalize this to "What if the sequence is (array t)?"
The first interpretation is a trivial design decision, but the second is
a fatal flaw in the scheme. I suspect this is really the point you were
trying to make: some sequences already have meaning in that context.