Getting action on your favorite D issues

[H. S. Teoh]

On Fri, Jun 05, 2020 at 04:53:28PM -0700, H. S. Teoh via Digitalmars-d wrote:
> On Fri, Jun 05, 2020 at 11:57:39PM +0200, ag0aep6g via Digitalmars-d wrote:
> [...]
> > 2) "bool can be both true and false"
> > https://issues.dlang.org/show_bug.cgi?id=20148
> > 
> > This one is just silly.
> [...]
> 
> Nah, it's not silly, it's just that DMD's backend produces code that
> exhibits quantum uncertainty:
[...]

For even more quantum fun:

----------
bool schrodingersCat() @safe {
	import std.random;
	union Box { bool b; int state; }
	Box u;
	u.state = uniform(2, int.max);
	return u.b;
}
void main() @safe {
	import std.stdio;
	bool b = schrodingersCat();
	if (b) writeln("alive");
	if (!b) writeln("dead");
}
----------

With LDC, this code will output either "alive" or "dead" with a roughly
50% probability of each.  So it's a classical observer.

With DMD, however, this code will perceive the quantum superimposition
directly and output both "alive" and "dead" every time.

:-D 

//

OK, I'll stop now. :-P


T

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