• Tobias Pankrath (25/25) Feb 25 2015 import std.container;
• sclytrack (5/30) Feb 25 2015 Ranges aren't containers. It's more like a view of a container
• Ivan Timokhin (2/3) Feb 25 2015 This call consumes all ranges stored in stack, so they're empty afterwar...
• Steven Schveighoffer (5/8) Feb 26 2015 This has to be a bug. stack[] should produce a range that can be
• Tobias Pankrath (5/17) Feb 26 2015 Haven't looked into it, but I'd rather say that writefln (or
• Steven Schveighoffer (7/25) Feb 26 2015 OK, this is more complex than I thought. Both stack[] and list[] are

"Tobias Pankrath" <tobias pankrath.net> writes:

import std.container;
import std.stdio;


void main()
{
    DList!int list;
    Array!(DList!int.Range) stack;
    foreach(i; 0 .. 4)
    {
       list.stableInsertBack(i);
       stack.insertBack(list[]);
    }

    writefln("list: %s", list[]); // fine
    writefln("stack: %s", stack[]); //fine

    foreach(s; stack[])
       writefln("s: %s", s); // all s are empty?

    writefln("stack: %s", stack[]); //not fine
}

It prints:

list: [0, 1, 2, 3]
stack: [[0], [0, 1], [0, 1, 2], [0, 1, 2, 3]]
s: []
s: []
s: []
s: []
stack: [[], [], [], []]

"sclytrack" <sclytrack fake.com> writes:

On Wednesday, 25 February 2015 at 09:07:17 UTC, Tobias Pankrath 
wrote:
 import std.container;
 import std.stdio;


 void main()
 {
    DList!int list;
    Array!(DList!int.Range) stack;
    foreach(i; 0 .. 4)
    {
       list.stableInsertBack(i);
       stack.insertBack(list[]);
    }

    writefln("list: %s", list[]); // fine
    writefln("stack: %s", stack[]); //fine

    foreach(s; stack[])
       writefln("s: %s", s); // all s are empty?

    writefln("stack: %s", stack[]); //not fine
 }

 It prints:

 list: [0, 1, 2, 3]
 stack: [[0], [0, 1], [0, 1, 2], [0, 1, 2, 3]]
 s: []
 s: []
 s: []
 s: []
 stack: [[], [], [], []]

Ranges aren't containers. It's more like a view of a container 
that gets smaller (or empty) the more you use it. There might not 
be a container behind a range.

Ivan Timokhin <timokhin.iv gmail.com> writes:

Tobias Pankrath wrote:

     writefln("stack: %s", stack[]); //fine

This call consumes all ranges stored in stack, so they're empty afterwards.

Steven Schveighoffer <schveiguy yahoo.com> writes:

On 2/25/15 4:58 AM, Ivan Timokhin wrote:
 Tobias Pankrath wrote:

      writefln("stack: %s", stack[]); //fine

 This call consumes all ranges stored in stack, so they're empty afterwards.

This has to be a bug. stack[] should produce a range that can be 
iterated without destroying the data in the container. If it doesn't, it 
should be supported.

-Steve

"Tobias Pankrath" <tobias pankrath.net> writes:

On Thursday, 26 February 2015 at 15:57:22 UTC, Steven 
Schveighoffer wrote:
 On 2/25/15 4:58 AM, Ivan Timokhin wrote:
 Tobias Pankrath wrote:

     writefln("stack: %s", stack[]); //fine

 This call consumes all ranges stored in stack, so they're 
 empty afterwards.

 This has to be a bug. stack[] should produce a range that can 
 be iterated without destroying the data in the container. If it 
 doesn't, it should be supported.

 -Steve

Haven't looked into it, but I'd rather say that writefln (or 
formattedWrite, or what is used) should only take ranges per ref, 
if they cannot be copied and cannot be saved.

Steven Schveighoffer <schveiguy yahoo.com> writes:

On 2/26/15 11:07 AM, Tobias Pankrath wrote:
 On Thursday, 26 February 2015 at 15:57:22 UTC, Steven Schveighoffer wrote:
 On 2/25/15 4:58 AM, Ivan Timokhin wrote:
 Tobias Pankrath wrote:

     writefln("stack: %s", stack[]); //fine

 This call consumes all ranges stored in stack, so they're empty
 afterwards.

 This has to be a bug. stack[] should produce a range that can be
 iterated without destroying the data in the container. If it doesn't,
 it should be supported.

 -Steve

 Haven't looked into it, but I'd rather say that writefln (or
 formattedWrite, or what is used) should only take ranges per ref, if
 they cannot be copied and cannot be saved.

OK, this is more complex than I thought. Both stack[] and list[] are 
providing copies.

I mistakenly thought that because stack prints empty that the list has 
been emptied. It hasn't, just the ranges are emptied.

Yes, I agree, it's writefln that should be fixed here.

-Steve