21.10.2013 17:55, Krzysztof Ciebiera пишет:
On Monday, 21 October 2013 at 10:41:38 UTC, Alexandr Druzhinin wrote:
21.10.2013 17:31, Krzysztof Ciebiera пишет:
void main()
{
int a[][] = [[1,2,3]];
foreach(x; a)
{
x[0] = 0;
x ~= 4;
}
writeln(a);
}
...
&) or [0,2,3,4] (python, C++ ref). But [0,2,3]? It was unpleasant
surprise.
It's expected.
foreach(ref x; a) == C++ with &
but without ref you get the first element of a - i.e. [1, 2, 3] then
set x[0] = 0 so you get [0, 2, 3]. But when you append 4 you append it
to local copy of x - because there is no 'ref'.
So, when exactly my local copy of data should be created? Now it is
created during appending element to an array (when I switch instructions
order, first append x ~= 4, then set x[0] to 0, as a result I get
[1,2,3]). Maybe I should get a warning (like when hiding variable from
outer scope)?
If you switch instruction order you create local copy and then set x[0]
in local copy so original is unchanged. But local copy creating depends
on several thing and happens not every appending in general. Your way is
not D-ish one. What do you want to do?
