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Issue: ADJUST-ARRAY-NOT-ADJUSTABLE (Version 6)
- To: Masinter.PA@Xerox.COM
- Subject: Issue: ADJUST-ARRAY-NOT-ADJUSTABLE (Version 6)
- From: Kent M Pitman <KMP@STONY-BROOK.SCRC.Symbolics.COM>
- Date: Wed, 15 Feb 89 09:43 EST
- Cc: CL-Cleanup@SAIL.Stanford.EDU
- In-reply-to: <890214-155752-10883@Xerox>
The message you sent to CL-Cleanup is only the earliest of a lot of
messages from that private conversation. To avoid replaying that whole
conversation, I offer here a summary of the discussion. For brevity,
I have paraphrased rather than quoted.
RPG - This proposal (v6) says ADJUST-ARRAY must signal. CLtL says
``is an error.''
Moon - This introduction of incompatible change was not intentional.
Still, ``must signal'' doesn't seem bad.
RPG - Eliminates option of ignoring error checking in highly optimized code.
Pitman - Can we compromise on ``should signal'' ?
RPG - OK.
RPG - Not sure if this is implied, should add:
5. The value of ADJUSTABLE-ARRAY-P on a simple array is unspecified.
No one objected.
RPG - Alternate presentation, incorporating new items and clarifications
per above, and changing subtle aspects of the presentation:
1. ADJUSTABLE-ARRAY-P is true of all arrays created with a true
:ADJUSTABLE option to MAKE-ARRAY. Whether ADJUSTABLE-ARRAY-P is
true of some other arrays is unspecified.
2. If MAKE-ARRAY is called with the :ADJUSTABLE, :FILL-POINTER,
and :DISPLACED-TO arguments each either unspecified or false, the
resulting array is a simple array. (This just repeats what CLtL
says on page 289, it's here to aid in understanding the next point.)
3. If MAKE-ARRAY is called with one or more of the :ADJUSTABLE,
:FILL-POINTER, or :DISPLACED-TO arguments true, whether the
resulting array is simple is unspecified.
4. If ADJUST-ARRAY is invoked on an array that was created without
supplying :ADJUSTABLE true, an error should be signaled, unless
ADJUSTABLE-ARRAY-P returns true on that array. ADJUST-ARRAY must
not signal the error if ADJUSTABLE-ARRAY-P is true for its first
argument.
5. The value of ADJUSTABLE-ARRAY-P on a simple array is unspecified.
KMP - Looks ok.
No one else commented.