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Issue: BIT-ARRAY-FUNCTIONS (version 6)
- To: Barry Margolin <barmar@Think.COM>
- Subject: Issue: BIT-ARRAY-FUNCTIONS (version 6)
- From: David A. Moon <Moon@STONY-BROOK.SCRC.Symbolics.COM>
- Date: Mon, 19 Jun 89 13:44 EDT
- Cc: CL-Cleanup@sail.stanford.edu
- In-reply-to: <19890619173133.4.BARMAR@OCCAM.THINK.COM>
Date: Mon, 19 Jun 89 13:31 EDT
From: Barry Margolin <barmar@Think.COM>
I'd like to suggest an additional change, which seems to be consistent
with the attitude about use of bit vectors expressed in the proposal.
The BIT and SBIT functions should return 0 if asked to access outside
the bit array. This would maintain the tautology
(bit (bit-XXX v1 v2) n) == (logXXX (bit v1 n) (bit v2 n))
If slowing down these functions (they'd be the only array accessors
REQUIRED to check the dimensions) is considered unacceptable, then a new
accessor should be added.
I don't like this idea.
If upon reflection you still like it, could you prepare an amendment
to bring up at the meeting next week?