Interesting Memory Optimization

[Xinok]

On Friday, 16 March 2012 at 15:41:32 UTC, Timon Gehr wrote:
> On 03/16/2012 03:28 PM, H. S. Teoh wrote:
>> More to the point, does dmd perform this optimization 
>> currently?
>>
>>
>> T
>>
>
> No.
>
> immutable string a = "123";
> immutable string b = a;
>
> void main(){writeln(a.ptr is b.ptr);} // "false"

It actually does, but only identical strings. It doesn't seem to 
do strings within strings.

void foo(string a){
	string b = "123";
	writeln(a is b);
}

void main(){
	string a = "123";
	string b = "456";
	string c = "123456";
	foo(a);
	foo(b);
	foo(c);
}

Prints:
true
false
false