Why is Python popular, while Lisp and Scheme aren't?
John Baxter
jwbaxter at spamcop.net
Mon Nov 11 11:53:28 EST 2002
In article <7h3lm402zq5.fsf at pc150.maths.bris.ac.uk>,
Michael Hudson <mwh at python.net> wrote:
> Carl Banks <imbosol at vt.edu> writes:
>
> > Dennis Lee Bieber wrote:
> > > As I recall, they also derive from the hardware that LISP was
> > > first
> > > implemented on -- C)ontents A)ddress R)egister, and C)ontents D)ata
> > > R)egister (or some variation thereof). Something to the effect that the
> > > original machine storage unit (words) effectively held two pointers,
> > > accessed as address and data...
> >
> >
> > Which is kind of funny. You'd expect the Data Register to point to
> > the nth item in the list, and Address Register to point to the next
> > cons cell. But the reverse is true.
>
> I think the d in cdr stands (stood) for decrement, not data. But the
> web seems confused on the issue. It just means "second half of cons
> cell" to me...
It was "decrement" in IBM's view of the machine, and in the usage of
those instructions which had the field.
--John
More information about the Python-list
mailing list