Regarding hex strings

[monarch_dodra]

On Friday, 19 October 2012 at 03:14:54 UTC, Marco Leise wrote:
>
> Hehe, I assume most of the regulars know this: DMD used to
> use a garbage collector that is disabled. Memory just isn't
> freed! Also it has copy on write semantics during CTFE:
>
> int bug6498(int x)
> {
>     int n = 0;
>     while (n < x)
>         ++n;
>     return n;
> }
> static assert(bug6498(10_000_000)==10_000_000);
>
> --> Fails with an 'out of memory' error.
>
> http://d.puremagic.com/issues/show_bug.cgi?id=6498
>
> So, as strange as it sounds, for now try not to write often or
> into large blocks. Using this knowledge I was sometimes able
> to bring down the memory consumption considerably by caching
> recurring concatenations of two strings or to!string calls.
>
> That said, appending single elements to an array may actually
> be better than using a fixed-sized one and have DMD duplicate
> it on every write. :p
>
> Please remember to give Don a cookie when he manages to change
> the compiler to modify in-place where appropriate.

I should have read your post in more detail. I thought you were 
saying that allocations are never freed, but it is indeed more 
than that: Every write allocates.

I just spent the last hour trying to "optimize" my code, only to 
realize that at its "simplest" (Walk the string counting 
elements), I run out of memory :/

Can't do much more about it at this point.