On Monday, 6 July 2015 at 03:02:59 UTC, Nicholas Wilson wrote:
On Monday, 6 July 2015 at 01:16:54 UTC, Peter wrote:
Hi,
I have a struct with arithmetic operations defined using
opBinary but array operations with arrays of it don't work.
struct Vector3 {
public double[3] _p;
...
Vector3 opBinary(string op)(in Vector3 rhs) const
if (op == "+"){
Vector3 result;
result._p[] = this._p[] + rhs._p[];
return result;
}
...
}
unittest{
auto a = Vector3([2.0, 2.0, 0.0]);
auto b = Vector3([1.0, 2.0, 1.0]);
Vector3[] c = [a];
Vector3[] d = [b];
Vector3 e = a + b; // works
Vector3[] f;
f[] = c[] + d[]; // Error: invalid array operation 'f[] =
c[] + d[]' because Vector3 doesn't support necessary
arithmetic operations
}
how can I get this to work?
Thanks
you need to define the slice operators. e.g.
auto opSlice() // no parameters to get whole slice eg. a[]
// can also define with opSlice(size_t i,
size_t j)
// for access like a[ i .. j]
{
return _p;
}
whoops. it may be complaining about lack of opSliceAssign
i.e. `f[] =`
again define this with no parameters for the whole slice or two
for a[i .. j] =
also note that you need to give memory for this array assignment
to go.
eg.
auto a = Vector3([2.0, 2.0, 0.0]);
auto b = Vector3([1.0, 2.0, 1.0]);
Vector3[] c = [a];
Vector3[] d = [b];
Vector3 e = a + b; // works
Vector3[] f;
f[] = c[] + d[];
will likely crash because `f` doesn't point to any allocated
memory.
initialising like
Vector3[] f = [Vector3()];
Enhancement Request to tell you the names of the missing methods
required
filed at
https://issues.dlang.org/show_bug.cgi?id=14772
