Against PEP 240

David C. Ullrich ullrich at
Fri Jun 1 16:43:24 CEST 2001

On Thu, 31 May 2001 21:07:26 -0400, "Tim Peters" < at>

>> Jurjen N.E. Bos contributed a Python implementation of the constructive
>> reals several years ago. ...
>[David C. Ullrich]
>> Really? You don't happen to recall where I can find this, do you?
>> (Um: or are you referring to the celebrated
>> At least in the version of I have the reals have arbitrary
>> but predetermined finite precision. If that's what you meant never mind.
>You have to represent reals as string-form function evaluations, then hook
>into the machinery that re-evaluates them with ever-increasing precision.
>It's barely documented and difficult to reverse-engineer.  The only "out of
>the box" way to do it is via the interactive functions that keep printing
>more and more digits until you interrupt them.  It's not enough *just* to
>use the Real class. 

Yeah, I figured later that I'd thought you were saying more than
you actually said here.

> If I ever get a free month, I'd like to package that
>machinery for non-interactive demand-driven use via a new class (which I
>expect is more what you have in mind).

Yup. (Don't get the idea I was or am requesting anything here, it's
certainly not something I need. Was just curious whether you were
talking about new Bos stuff I hadn't heard of. The idea of _reals_
with actual infinite precision is fascinating, but at least
from my point of view that's all it is.)

>> Those wacky reals. Makes you wonder how they got the name.
>Probably some Dutch guy; heck, they even name languages after snakes.

I didn't know that, thanks.

David C. Ullrich
"Sometimes you can have access violations all the 
time and the program still works." (Michael Caracena, 
comp.lang.pascal.delphi.misc 5/1/01)

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