Error on recursive alias

[Johan Mollevik]

bearophile wrote:

> Johan Mollevik:
> 
>> x and y are the two dimensional indices into the 4x4 array
>> block and v
>> is the vallue at block[y][x]
> 
> OK. Something like this?
> 
> 
> import std.stdio, std.typecons;
> 
> struct NaturalScan(T) {
>      T[][] data;
>      size_t r, c;
> 
>      @property bool empty() const pure nothrow {
>          return r == data.length;
>      }
> 
>      @property Tuple!(size_t, size_t, T) front()
>      const pure nothrow {
>          return typeof(return)(r, c, data[r][c]);
>      }
> 
>      void popFront() pure nothrow {
>          c = (c + 1) % data[r].length;
>          if (c == 0)
>              r++;
>      }
> }
> 
> NaturalScan!T naturalScan(T)(T[][] m) {
>      return typeof(return)(m);
> }
> 
> void main() {
>      auto mat = [[10, 20], [30, 40, 50], [60, 70]];
>      foreach (r, c, v; mat.naturalScan)
>          writefln("%d %d %d", r, c, v);
> }
> 
> 
> Bye,
> bearophile

That looks like it might work for 2 dimensions and as that is the use 
case I have right now I might settle for that. (and I can add more 
overloads manually if needed)

The original code was genereal enough to handle any number of 
dimensions thou.

Bassically this would work like this

uint[][][] array=...

foreach(x,v;opApplyN(array)){//using only one index (x)
	//v has type uint[][]
}


foreach(x,y,v;opApplyN(array)){//using two indeces (x,y)
	//v has type uint[]
}


foreach(x,y,z,v;opApplyN(array)){//using three index (x,y,z)
	//v has type uint
}

So if someone know anything of why I get the error on recursive aliases 
I might try to get that working again otherwise I might try your code 
as it is enough for now

Thnks for the help by the way