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Speaking of issues left of the Ballots ...
- To: common-lisp at SU-AI
- Subject: Speaking of issues left of the Ballots ...
- From: JONL at PARC-MAXC
- Date: Thu, 02 Dec 1982 09:04:00 -0000
At the meeting in August, I mentioned that LOAD-BYTE and DEPOSIT-BYTE
had been dropped without discussion. Around that time also,
EAK and I offered reasons why they are better choices than LDB and
DPB. I hope that after considering them, you'll feel more inclined
to at least include LOAD-BYTE in the white pages, regardless of the
status of LDB.
1) LDB presents us with a fatal flaw -- either we break compatibility
with the LispMachine definition (and the PDP10 MacLisp definition)
or we are stuck with a primitive which cant address more than 63
bits worth of byte, nor any bits beyond the 64'th. Despite the
manual's best intention of abstracting the notion of a "byte
specifier" (section 12.7), the LispM/MacLisp practice is to use a
4-digit octal number. When, in existing code, the bytespec
isn't the PDP-10 determined 4 octal digits (say, some variable)
then a mechanical converter *cant't* turn that code into
the use of the BYTE function (unless "byte specifiers" are a new
data type which will be type-certified by each use of LDB; for
if such a conversion happened with out type-integrity, then assuming
that a "byte specifier" is still some integer, there would be
no guarantee that the conversion wasn't happening on an integer
already converted elsewhere.
2) LDB and LOAD-BYTE tend to treat ingeters as sequences; as such, the
syntax of subsequence specification is totally out of character with
the other sequence functions. At the very least, we should have
(INTEGER-SUBSEQ <n> <start-position> &optional <end-position>)
which would translate into something like a currently-defined LDB
with bytespec of (BYTE (1+ (- <start> <end>)) <start>). It may be
that I've forgotten EAK's original complaint against LDB, but I
thought it was essentially this.
3) the name Lid-ub (or Ell-dib, if you prefer) is the worst asssault on
the reasonableness of names in the CommonLisp lexicon. Who, who
hasn't been contaminated with PDP10 lore, would think this an
appropriate name? How can a community as sensitive to the
implications of nomenclature as to change "haulong" into
"integer-length" not be swayed to prefer "integer-subseq" to L.D.B.