• Robert (36/36) Oct 18 2011 Hello,
• bearophile (14/18) Oct 18 2011 Even when you think you have found a bug in D, I suggest you to ask firs...

Robert <robert.welin gmail.com> writes:

Hello,
When I try to initialize a dynamic rectangular array, the length of the inner
arrays does not seem to be preserved outside the scope of initialization. I'm
not proficient enough in D to say that my code is completely correct, but if
I am correct this might be a serious bug. See attached test code.
Many thanks
Robert
begin 644 arrayinit.d
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end

bearophile <bearophileHUGS lycos.com> writes:

Robert:

 When I try to initialize a dynamic rectangular array, the length of the inner
 arrays does not seem to be preserved outside the scope of initialization. I'm
 not proficient enough in D to say that my code is completely correct, but if
 I am correct this might be a serious bug. See attached test code.

Even when you think you have found a bug in D, I suggest you to ask first in
D.learn newsgroup. D.bugs is not meant for free discussions.

Regarding your code, you have hit a bug-prone spot of D, but I think D is
correct here.

This code of yours:

    foreach (i, r; grid)
    {
        r.length = width;

Write it like:

    foreach (i, ref r; grid)
    {
        r.length = width;

Because D arrays are value types that contain a pointer to the storage. So the
r inside the foreach is a copy, you aren't modifying the original. See the D
ABI to see how D dynamic arrays are implemented on their surface (it doesn't
explain how array append is managed at runtime).

Bye,
bearophile