Oh Dear

[bearophile]

Michiel Helvensteijn:
> Walter, surely this test shouldn't take more than a minute for you (or
> anyone else with a D compiler installed). Just see what DMD outputs for:
> 
>   8  /   3
>   8  / (-3)
> (-8) /   3
> (-8) / (-3)
>   8  %   3
>   8  % (-3)
> (-8) %   3
> (-8) % (-3)

You don't know codepad.org :-)

D version:
http://codepad.org/Mbi9HBjz

void main() {
    writefln(   8  /   3);
    writefln(   8  / (-3));
    writefln( (-8) /   3);
    writefln( (-8) / (-3));
    writefln(   8  %   3);
    writefln(   8  % (-3));
    writefln( (-8) %   3);
    writefln( (-8) % (-3));
}

D output:
2
-2
-2
2
2
2
-2
-2

-------------

Python version:
http://codepad.org/Mbi9HBjz

print   8  //   3
print   8  // (-3)
print (-8) //   3
print (-8) // (-3)
print   8  %   3
print   8  % (-3)
print (-8) %   3
print (-8) % (-3)

Python output:

2
-3
-3
2
2
-1
1
-2

---------------------

BCS:

>Short of overflow detection (and the overhead that causes) I think this is an issue inherent to discreet systems (a.k.a. all computer systems) that we just have to live with.<

I don't understand what's the purpose of overflow detection in this context. Are those differences between the D and Python output caused by overflows?

Bye and thank you,
bearophile