Re: Why not a setf-able NIL ?

kodifik@xxxxxxxxxxxxx writes:

Pascal Costanza wrote:
(loop until (zerop number) ...)
Quite right, doctor. I am not sure the example (loop while number...)
was very fortunate.
What I talked about is something more far-reaching: it would allow for
instance to change the behavior of a running program on the fly
without rewriting it, just by reassigning the symbol nil.
In your solution, the finalization condition is hard-coded.
I am asking why is nil hard-coded in Common Lisp, when it has always
been said that hard-coding things is a mark of bad program design.
Talking about the possibility of being free to redefine nil, does not
mean I would want to do it.

Indeed. Personnaly, I'm quite worried by the hardcoding of neutral
charge into neutron. Why are we not able to rebind all the neutrons
in the universe to some charge? Try to imagine what would happen if
suddenly all the neutrons were -2e.

--
__Pascal Bourguignon__ http://www.informatimago.com/

There is no worse tyranny than to force a man to pay for what he does not
want merely because you think it would be good for him. -- Robert Heinlein
.