opIndex operators

[bearophile]

gedaiu:

> What i want to create, is an array structure like the one from 
> PHP where array levels are not fixed and the sintax to access 
> rhe values is val[][] so returning a reference to a struct that 
> have the same type as the current type is useful.
>
> there is a way to do this in D?

Instead of returning float as in my case, you return something 
else that has opIndex and opIndexAssign. This way you can pile up 
the []:


import std.stdio;

struct Foo {
     ref Foo opIndex(in size_t i) {
         writeln("opIndex: ", i);
         return this;
     }

     void opIndexAssign(in float value, in size_t i) {
         writeln("opIndexAssign: ", value, " ", i);
     }
}

void main() {
     Foo f;
     f[1] = 2;
     f[3][4] = 5;
     f[6][7][8] = 9;
}


That outputs:

opIndexAssign: 2 1
opIndex: 3
opIndexAssign: 5 4
opIndex: 6
opIndex: 7
opIndexAssign: 9 8

Bye,
bearophile