On Tuesday, 25 October 2022 at 20:12:25 UTC, Paul Backus wrote:
On Tuesday, 25 October 2022 at 17:54:16 UTC, Salih Dincer wrote:
On Tuesday, 25 October 2022 at 17:18:35 UTC, Paul Backus wrote:
It's not a bug. They're pointing to the exact same instance
of `A` in memory:
I don't understand? So I don't understand why it causes
problems with dynamic arrays! So why is there nothing wrong
with the static array in the example below?
Static arrays are value types. When you copy a static array,
the copy's data is stored in a separate block of memory from
the original:
```d
int[1] a = [1];
int[1] b = a;
assert(&a[0] !is &b[0]); // different memory
```
Dynamic arrays are reference types. When you copy a dynamic
array, both copies point to the same block of memory:
```d
int[] a = [1];
int[] b = a;
assert(&a[0] is &b[0]); // same memory
```
In order to create a copy of a static array with its own block
of memory, separate from the original, you have to use the
built-in `.dup` method:
```d
int[] a = [1];
int[] b = a.dup;
assert(&a[0] !is &b[0]); // different memory
```
This is interesting, I understand the point of "reference vs
copy", and I'm OK with this design choice of, but I wonder in the
case of newcomers if this is a case the generate more problem
understanding this rules, like we are having here.
Matheus.
