Re: Why not a setf-able NIL ?
- From: Matthias Benkard <mulkiatsch@xxxxxxxxx>
- Date: Fri, 3 Oct 2008 01:06:45 -0700 (PDT)
On 2 Okt., 23:39, "josephoswald...@xxxxxxxxx" <josephosw...@xxxxxxxxx>
wrote:
You can't change pi, you change the formulas for the geometric
quantities, for instance that the angles of a triangle sum to pi + A/
a^2, instead of simply pi.
Otherwise, your probability and integration and all sorts of other
libraries will start to give wrong answers, because you have changed
the formula for a bell-curve and the residue of integrating around a
pole, and all the other things that pi connects to.
Exactly. Not to mention that in case your system defines -1 as
(defconstant -1 (exp (* pi #(0 1))))
you will suddenly get strange results when evaluating (- 1 1), which
may well be implemented as (+ 1 -1).
Constants are constants for a reason. They provide you with the
fundamentals which you can build your system on. Because of this,
they HAVE TO BE invariant! You need to be able to rely on them never
changing.
Computer science may be considered a branch of mathematics. In
mathematics, it just doesn't make sense to dynamically “redefine” the
fundamentals that you have built your whole system of reasoning on top
of! Especially in logics. Redefine falsity? Umm... no, thanks.
Matthias
.
- References:
- Why not a setf-able NIL ?
- From: kodifik
- Re: Why not a setf-able NIL ?
- From: Pascal Costanza
- Re: Why not a setf-able NIL ?
- From: kodifik
- Re: Why not a setf-able NIL ?
- From: Pascal J. Bourguignon
- Re: Why not a setf-able NIL ?
- From: Matthias Buelow
- Re: Why not a setf-able NIL ?
- From: kodifik
- Re: Why not a setf-able NIL ?
- From: josephoswald+gg@xxxxxxxxx
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