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Vectors versus Arrays
- To: Dick Gabriel <RPG at SU-AI>
- Subject: Vectors versus Arrays
- From: MOON at SCRC-TENEX
- Date: Mon, 13 Sep 1982 01:23:00 -0000
- Cc: common-lisp at SU-AI
I think the point here, which perhaps you don't agree with, is that
"vector" is not a useful concept to a user (why is a vector different from
a 1-dimensional array?) It's only a useful concept to the implementor, who
thinks "vector = load the Lisp pointer into a base register and index off
of it", but "array = go call an interpretive subroutine to chase indirect
pointers", or the code-bummer, who thinks "vector = fast", "array = slow".
Removing the vector/array distinction from the guts of the language is in
much the same spirit as making the default arithmetic operators generic
across all types of numbers.
I don't think anyone from "the Symbolics crowd convinced us that changing
things were too hard for them"; our point was always that we thought it was
silly to put into a language designed in 1980 a feature that was only there
to save a few lines of code in the compiler for the VAX (and the S1), when
the language already requires declarations to achieve efficiency on those
If you have a reasonable rebuttal to this argument, I at least will listen.
It is important not to return to "four implementations going in four different