Steven Schveighoffer wrote:
In many other posts, people have been festering over dropping T[new] and
not having a reference array type. The argument is (and forgive me if
this is a strawman, someone from the other side can post if I'm
incorrect): If we make arrays a separate type from slices, and only
allow appending on arrays, then we solve the stomping problem and the
hard-to-determine reallocating problem. For those who are unfamiliar
with these problems, I'll try to outline them at the bottom of the post.
I contend that even if we make arrays a separate type, even if arrays
are made a true reference type, slices will still suffer from the same
hard-to-determine reallocation problem *unless* we make slices fatter.
My proof is as simple as an example. Assume 'Array' is the new type for
an array:
auto a = new Array!(int)(15); // allocate an array of 15 integers, all 0
auto s = a[0..5];
a ~= [1,2,3,4,5];
a[0] = 1.
Now, what does s[0] equal?
Array may include a field
bool sliceExtracted;
that is set to true whenever you take a slice from the array and set to
false whenever the array's data is reallocated. The array's
documentation could mention that ~= is amortized constant if there are
no intervening slicing operations.
Andrei
