• =?UTF-8?B?Ik5vcmRsw7Z3Ig==?= (13/13) Feb 18 2015 At
• ketmar (3/4) Feb 18 2015 i don't think so. you can use heap-allocated structs, of course, or mayb...
• =?UTF-8?B?QWxpIMOHZWhyZWxp?= (55/56) Feb 18 2015 move() does avoid the post-blit but you get many destructions in return:

=?UTF-8?B?Ik5vcmRsw7Z3Ig==?= <per.nordlow gmail.com> writes:

At

https://github.com/nordlow/justd/blob/master/knet/association.d#L59

I'm constructing an array of ranges that are used further down in 
the function contextOf.

The expression

     nds.map!(nd => gr.dijkstraWalker(nd, ...)).array;

however triggers postblits for the range DijkstraWalker returned 
by the instantiator dijkstraWalker.

Can this be avoided somehow?

I'm guessing that move construction plays a key role here.

Note that I can't remove the .array as they required to be 
l-values because their iteration to have side-effects at the end 
of the function contextOf().

ketmar <ketmar ketmar.no-ip.org> writes:

On Wed, 18 Feb 2015 22:51:17 +0000, Nordl=C3=B6w wrote:

 Can this be avoided somehow?

i don't think so. you can use heap-allocated structs, of course, or maybe=20
`RefCounted!` can do the trick, but i not tried it.=

=?UTF-8?B?QWxpIMOHZWhyZWxp?= <acehreli yahoo.com> writes:

On 02/18/2015 02:51 PM, "Nordlöw" wrote:

 I'm guessing that move construction plays a key role here.

move() does avoid the post-blit but you get many destructions in return:

import std.stdio;
import std.algorithm;
import core.memory;

struct Graph
{}

struct DW
{
     int i;

     this(int i)
     {
         writefln(" this() for %s", i);
         this.i = i;
     }

     ~this()
     {
         writefln("~this() for %s", i);
     }

     this(this)
     {
         writefln("this(this) for %s", i);
         assert(false, "Oops");
     }
}

DW dw(Graph gr, int i)
{
     return DW(i);
}

void main()
{
     auto gr = Graph();
     auto arr = [ 1, 2, 3 ];
     auto dws = new DW[arr.length];

     foreach (i, el; arr) {
         auto source = gr.dw(el);
         move(source, dws[i]);
     }

     writeln(dws);
}

The output:

  this() for 1
~this() for 0
~this() for 0
  this() for 2
~this() for 0
~this() for 0
  this() for 3
~this() for 0
~this() for 0
[DW(1), DW(2), DW(3)]
~this() for 3
~this() for 2
~this() for 1

Ali