Code:
import std.stdio;
import std.math;
void main(string[] args)
{
writefln("test: %s%6s", "pow()", "^^");
writefln("-3^^0: %s%10s", pow(-3, 0), -3^^0);
writefln("-2^^0: %s%10s", pow(-2, 0), -2^^0);
writefln("-1^^0: %s%10s", pow(-1, 0), -1^^0);
writefln(" 0^^0: %s%10s", pow( 0, 0), 0^^0);
writefln(" 1^^0: %s%10s", pow( 1, 0), 1^^0);
writefln(" 2^^0: %s%10s", pow( 2, 0), 2^^0);
writefln(" 3^^0: %s%10s", pow( 3, 0), 3^^0);
}
Outputs:
test: pow() ^^
-3^^0: 1 -1
-2^^0: 1 -1
-1^^0: 1 -1
0^^0: 1 1
1^^0: 1 1
2^^0: 1 1
3^^0: 1 1
Note that zero, and positive to the power of 0 match the return value of pow(). But negative numbers to the power of 0 don't.
Marking as major because this could cause confusion.
Regards
Comment #1 by ibuclaw — 2010-11-05T13:26:12Z
Hmm... actually, I think not now.
Part of the confusion was that it gets parsed down like so:
=> -3 ^^ 0
=> -(3 ^^ 0)
=> -(1)
When I expected it to be:
=> -3 ^^ 0
=> ((-3) ^^ 0)
=> (1)
I'll assume that this behaviour is normal, sorry for the noise. :~)
Comment #2 by bearophile_hugs — 2010-11-05T14:03:12Z
I am not saying this is bad or good, but I want to show what Python 2.6.6 does (the same as D, it seems):
>>> -1**0
-1
>>> pow(-1, 0)
1
(I recall some threads about this behaviour in the Python newsgroups, some person was not happy of it).
Comment #3 by bugzilla — 2010-11-08T02:14:20Z
The negation and exponentiation operators have the same relative precedence in D as in mathematics. I would be extremely surprised if I wrote -2^^2 and got 4.
Correcting the resolution of this bug, since nothing was fixed.