Python 3000 deat !? Is true division ever coming ?

[Dave Hansen]

Caution: bunny trail ahead.  Feel free to skip this message, as it
contains no useful content whatever...

On Sat, 18 Feb 2006 12:09:02 +1100 in comp.lang.python, Steven
D'Aprano <steve at REMOVETHIScyber.com.au> wrote:

[...]
>
>I've never even used Matlab. But I have a calculator. (Actually I have
>about half a dozen calculators.) In every single one of them, 1/2 gives
>0.5 instead of 0. I'm even capable of doing that calculation in my head.
>So I don't think true division is only in Matlab.

I have three calculators: an HP-48S, and HP-16C, and NeoCal on my
Palm.

On the HP-48S: 1 <Enter> 2 / -> 500.000000000E-3
On the HP-16C: 1 <Enter> 2 / -> 0 h (c)
On NeoCal:     1 <Enter> 2 / -> 500.e-3

Note: the (c) on the 16C indicates the "carry" bit was set, which the
16C does whenever the remainder of a division is nonzero.

Caveats: The result for each calculator depends on its "mode."  In
"programmer" mode, each calculator performs a truncating integer
division.  The 16C is in programmer mode by default.  The 48S is
almost never in programmer mode since I bought the 16C.  NeoCal goes
into programmer mode about 25% of the time I use it.  It was in
"Statistics" mode when I powered it up just now.

>
>
>> As you pointed out: the "true division" part of "Python3000" might be
>> one of the "scariest" and should therefore be pointed out already in
>> the tutorial !!  (It would look quite ugly to newcomers, though)

If you want ugly, consider Pascal.  The / operator could not perform
an integer divide, and a compile-time error was generated if you
attempted to use it with integer operands.  The integer divide
operator was 'div', e.g. "i = j div k"

>
>The tutorial shouldn't talk about Python3000 at all. What would be the
>point of that? The tutorial is there to teach about the way Python works
>now, not to make guesses and prediction about how it will work some time
>in the indefinite future.
>
>
>> Having said that:  I would vote against EVER introducing true division
>> as default - because it will just PISS too many (long time python)
>> people OFF. ;-)
>
>Do you realise that the reason true division was introduced into Python
>was because many long-time Python programmers requested it? So far from
>annoying them, it is a feature that most Python programmers are waiting
>for.

I am a relatively long-time user (since about 1999) of Python, but I
mainly program in C.  "True" division probably wouldn't p*ss me off
too bad, and I certainly wouldn't have a problem with new scripts I
wrote.  But if it broke old scripts, I wouldn't be extremely happy.

FWIW, ISTM that "true" division would be better implemented by the new
// operator, leaving the behavior of / unchanged.  But that's probably
just me.

Regards,
                                        -=Dave

-- 
Change is inevitable, progress is not.