On Saturday, 9 January 2021 at 02:07:50 UTC, Ali Çehreli wrote:
On 1/8/21 3:10 PM, tsbockman wrote:> On Friday, 8 January 2021 at 20:43:37 UTC, Andrey wrote: >> Hello, >> >>> struct Value >>> { >>> int value; >>> string data; >>> string[] text;The destination is immutable(char)[]. The characters cannot be changed. We can still append but other slices that share the same data is protected by D's no-stomp decision.>>> } >>> >>> void test(const ref Value value) >>> { >>> Value other = void; >>> other.text = value.text;Even though the source is 'const ref', other.text is a copy of the slice object (the pointer and the length). Because the elements are immutable, other.text cannot mutate value.text.
Remember, `string[]` means `immutable(char)[][]`, so there are actually two layers of pointer + length here. The outer one is copied, but the inner one is not, which means that mutating `other.text[0]` would also mutate `value.text[0]` if this assignment were allowed.
