Bartosz Milewski wrote:
Andrei Alexandrescu Wrote:
My concern is the semantics of the language. As it is defined right
now, a conforming implementation is free to use a quantum random
number generator to decide whether to re-allocate or not. Is it
likely? I don't think so; but the non-determinism is part of the
semantics of D arrays.
It would not be difficult to specify in the language definition
(and TDPL) that behavior is deterministic for a given platform. I
think this has some impact on the freedom of the memory allocator,
but probably not major.
Actually this wouldn't fix the problem. Although this would make the
program deterministic, it would still exhibit chaotic behavior (and
chaos is a pretty good simulator of non-determinism--see random
number generators).
I am glad you have also reached that conclusion.
An input string that is one character longer than in the previous run
in one part of the program could cause change in allocation in a
completely different part of the program (arbitrary long distance
coupling).
Then you must restart your argument which was centered around
non-determinism. It starts like that: "I read Andrei's chapter on arrays
and there's one thing that concerns me. When a slice is extended, the
decision to re-allocate, and therefore to cut its connection to other
slices, is non-deterministic."
Andrei
