Memory allocation in D (noob question)

[Steven Schveighoffer]

"Derek Parnell" wrote
> On Wed, 05 Dec 2007 16:18:46 +0000, Regan Heath wrote:
>
>> [example pasted again for clarity]
>>
>>  > string ab = "ab".idup;
>>  > string a = ab[0..1];
>>  > a ~= "c";
>>  > writefln("ab = ",ab); // also outputs "ac"
>
> However, this is fine ...
>
> string ab = "ab";
> string a = ab[0..1];
> a ~= "c";
> writefln("ab = ",ab); // outputs "ab"
> writefln("a  = ",a);  // outputs "ac"
>
> So it seems that the '.idup' property is affecting things.

Yes, I noticed that too.  However, it's simply the non-deterministic 
behavior of the ~= operator that is causing this.  For literal strings, I 
suspect they are not allocated by the GC, and so the GC can't extend them, 
so the normal behavior kicks in.  But idup is supposed to give me an 
invariant array.  The code is still changing invariant data...

-Steve