Stewart Gordon wrote:
Walter Bright wrote:
<snip>
Under the hood, a T[new] will be a single pointer to a library defined
type. This library defined type will likely contain three properties:
size_t length;
T* ptr;
size_t capacity;
The usual array operations will work on T[new] as well as T[].
<snip>
Would new T[10] allocate this structure and the array data on a single
GC block, or on two separate blocks?
That's up to the implementation.
And when the array is reallocated,
will the structure move with it?
No, that would defeat the whole purpose of making T[new] a reference
type. With it being a reference type:
T[new] a = ...;
T[new] b = a;
a.length = ...
... b.length changes too ...
I suppose it depends on whether you want T[new] to be
(a) something whereby all references persist as the array is reallocated
(b) merely a reference to an allocated array as opposed to an array slice
If (a), this is currently achievable with a T[]*.
If (b), what might work well is a structure like
size_t length;
size_t capacity;
T[capacity] data;
meaning still only one allocation and only one level of indirection when
one is used. And the T[new] variable itself would simply hold &data[0].
Moreover, would whatever happens solve such const/invariant holes as bug
2093?
I believe it does.
Stewart.
