On Wednesday, 5 February 2014 at 19:48:58 UTC, Namespace wrote:
Hm, you're right. Would have been nice if the nice syntax could be retained, instead of further unsightly library solution.
The thing is most slices don't need anything special - they are inspected, but not stored. Since they aren't stored, the allocation isn't this function's problem.
Yesterday, I wrote a post with a function int average(int[] numbers) as an illustration here. numbers might be on the stack, the Gc heap, or a refcounted array, and none of that matters. Average just looks at it. As long as there isn't something like another thread that frees the memory in the middle of average's execution, it will be fine. (And if there is a magic thread freeing things willy nilly, now that's a real WTF!)
This is why the borrowed idea (implemented by escape analysis in my mind, i think that would work and get us most the benefits without all of Rust's complexity) is nice: with a borrowed pointer, you explicitly know freeing it isn't your problem. You don't have to count or carry a refcount, you don't have to run the gc, you don't have to call free. You can take a lightweight slice and use it with confidence... as long as it doesn't escape the scope and thus accidentally stick around after the function returns.
