Error: array operation d1[] + d2[] without assignment not implemented

2014-09-13 Thread deed via Digitalmars-d-learn 

struct Vector (T)
{
  T[]arr;
  void opSliceAssign (T[] a) { arr[] = a[]; }
}
unittest
{
  auto v = Vector!double([1, 2]);
  double[] d1 = [11, 12];
  double[] d2 = [21, 22];
  double[] d3 = new double[](2);
  d3[] = d1[] + d2[];
  assert (d3 == [11.+21., 12.+22.]);
  assert (is(typeof(d1[] + d2[]) == double[]));
  v[] = d1[]  // Fine
  v[] = d1[] + d2[];  // Error: array operation d1[] + d2[] 
without assignment not implemented

}

How can opSliceAssign be defined to make this work?

Re: Error: array operation d1[] + d2[] without assignment not implemented

2014-09-13 Thread Ilya Yaroshenko via Digitalmars-d-learn 

On Saturday, 13 September 2014 at 14:18:57 UTC, deed wrote:

struct Vector (T)
{
  T[]arr;
  void opSliceAssign (T[] a) { arr[] = a[]; }
}
unittest
{
  auto v = Vector!double([1, 2]);
  double[] d1 = [11, 12];
  double[] d2 = [21, 22];
  double[] d3 = new double[](2);
  d3[] = d1[] + d2[];
  assert (d3 == [11.+21., 12.+22.]);
  assert (is(typeof(d1[] + d2[]) == double[]));
  v[] = d1[]  // Fine
  v[] = d1[] + d2[];  // Error: array operation d1[] + d2[] 
without assignment not implemented

}

How can opSliceAssign be defined to make this work?


Hi!

struct Vector (T)
{
T[]arr;
T[] opSlice() { return arr; }
}
Vector!double v;
double[] d;
v[][] = d[] + d[];

//first [] call opSlise, second [] for array syntax

Best Regards,
Ilya

Re: Error: array operation d1[] + d2[] without assignment not implemented

2014-09-13 Thread Ilya Yaroshenko via Digitalmars-d-learn 


Operations like ar1[] op= ar2[] op ar3[] is only for arrays.
There is no operator overloading for this staff.

Re: Error: array operation d1[] + d2[] without assignment not implemented

2014-09-13 Thread deed via Digitalmars-d-learn 

Hi!

struct Vector (T)
{
T[]arr;
T[] opSlice() { return arr; }
}
Vector!double v;
double[] d;
v[][] = d[] + d[];

//first [] call opSlise, second [] for array syntax

Best Regards,
Ilya


Thanks for your suggestion. It's not as attractive though, it 
would be the same as v.arr[] = ..., exposing the naked array. The 
syntax also becomes a bit confusing.


With alias this it works, but functionality is lost. See
http://dpaste.dzfl.pl/35081c1f1745

It feels not consistent, so I guess that's the reason for the 
not implemented message.