• Yuxuan Shui (9/9) May 15 2017 Suppose I have a
• Stanislav Blinov (4/13) May 15 2017 moveEmplace is for moving an initialized object into an
• Yuxuan Shui (3/21) May 15 2017 Can I expand an array with uninitialized object? Or can I rely on
• Stanislav Blinov (5/7) May 15 2017 Built-in arrays always default-initialize their elements. If you
• Yuxuan Shui (2/10) May 15 2017 I just wish ~= could take moved objects.
• biocyberman (18/27) May 18 2017 Judging form the way you write the struct. It is of C/C++ style.

Yuxuan Shui <yshuiv7 gmail.com> writes:

Suppose I have a

struct A {
    disable this(this);
} x;

How do I append it into an array?

Do I have to do

array.length++;
moveEmplace(x, array[$-1]);

?

Stanislav Blinov <stanislav.blinov gmail.com> writes:

On Monday, 15 May 2017 at 21:38:52 UTC, Yuxuan Shui wrote:
 Suppose I have a

 struct A {
    disable this(this);
 } x;

 How do I append it into an array?

 Do I have to do

 array.length++;
 moveEmplace(x, array[$-1]);

 ?

moveEmplace is for moving an initialized object into an 
uninitialized one. Use the two-argument move() function:

move(x, array[$-1]);

Yuxuan Shui <yshuiv7 gmail.com> writes:

On Monday, 15 May 2017 at 23:36:06 UTC, Stanislav Blinov wrote:
 On Monday, 15 May 2017 at 21:38:52 UTC, Yuxuan Shui wrote:
 Suppose I have a

 struct A {
    disable this(this);
 } x;

 How do I append it into an array?

 Do I have to do

 array.length++;
 moveEmplace(x, array[$-1]);

 ?

 moveEmplace is for moving an initialized object into an 
 uninitialized one. Use the two-argument move() function:

 move(x, array[$-1]);

Can I expand an array with uninitialized object? Or can I rely on 
the compiler to optimize the initialization away?

Stanislav Blinov <stanislav.blinov gmail.com> writes:

On Tuesday, 16 May 2017 at 01:22:49 UTC, Yuxuan Shui wrote:

 Can I expand an array with uninitialized object? Or can I rely 
 on the compiler to optimize the initialization away?

Built-in arrays always default-initialize their elements. If you 
need something that unsafe, there's std.array.uninitializedArray:

http://dlang.org/phobos/std_array.html#uninitializedArray

What are you trying to achieve?

Yuxuan Shui <yshuiv7 gmail.com> writes:

On Tuesday, 16 May 2017 at 01:34:50 UTC, Stanislav Blinov wrote:
 On Tuesday, 16 May 2017 at 01:22:49 UTC, Yuxuan Shui wrote:

 Can I expand an array with uninitialized object? Or can I rely 
 on the compiler to optimize the initialization away?

 Built-in arrays always default-initialize their elements. If 
 you need something that unsafe, there's 
 std.array.uninitializedArray:

 http://dlang.org/phobos/std_array.html#uninitializedArray

 What are you trying to achieve?

I just wish ~= could take moved objects.

biocyberman <biocyberman gmail.com> writes:

On Monday, 15 May 2017 at 21:38:52 UTC, Yuxuan Shui wrote:
 Suppose I have a

 struct A {
    disable this(this);
 } x;

 How do I append it into an array?

 Do I have to do

 array.length++;
 moveEmplace(x, array[$-1]);

 ?

  Judging form the way you write the struct. It is of C/C++ style. 
With that said,
it's not clear what you are trying to do. There is a basic 
reference about array here:
http://dlang.org/spec/arrays.html

And this works:

cat arrayappend.d
// arrayappend.d content
unittest {
   auto a = [1, 2];
   a ~= 3;
   assert( a == [1, 2, 3]);
}
// Finish content

Running test:

rdmd -unittest -main arrayappend.d

No error message means the test passes.