void main( char[][] arg )
{
  float[2][3]     A;

  A[0][0] = 1;
  A[0][1] = 2;
  A[0][2] = 3;  // << error here
}

test.d(10): array index [2] is outside array bounds [0 .. 2]


-David

David Medlock wrote:
> 
> void main( char[][] arg )
> {
>   float[2][3]     A;
> 
>   A[0][0] = 1;
>   A[0][1] = 2;
>   A[0][2] = 3;  // << error here
> }
> 
> test.d(10): array index [2] is outside array bounds [0 .. 2]
> 
> 
> -David

It's not a compiler bug. You're using a D-style array declaration. This line:
//  float[2][3]     A;
says:
"array of 3 arrays of 2 floats"

D-style declarations read from left ro right. So basically:
float[2] is a 2 element array of float
float[2][3] is a 3 element array of float[2]

On the other hand, A[a][b] reads in the other direction. Actually it's quite logical if you think about it...

You should either declare the array as:
//  float A[3][2]

... or index the array like this:
//  A[0][0] = 1;
//  A[1][0] = 2;
//  A[2][0] = 3;


-- 
Tomasz Stachowiak  /+ a.k.a. h3r3tic +/

Tom S wrote:
> You should either declare the array as:
> //  float A[3][2]

Ooops, it should read:

//  float A[2][3];


-- 
Tomasz Stachowiak  /+ a.k.a. h3r3tic +/

Tom S wrote:
> Tom S wrote:
> 
>> You should either declare the array as:
>> //  float A[3][2]
> 
> 
> Ooops, it should read:
> 
> //  float A[2][3];
> 
> 

Hmmm Pretty confusing...but se la vi.

Thanks, Tom.

Tom S wrote:
> It's not a compiler bug. You're using a D-style array declaration. This line:
> //  float[2][3]     A;
> says:
> "array of 3 arrays of 2 floats"
> 
> D-style declarations read from left ro right.

Tom is basically right, but I think he meant to say "D-style declerations read from right to left" rather than the other way.  :)  It really does simplify things a fair amount, though.  To help get your mind around it, consider some declerations:

// read: x is: array of: pointer to: int
int*[] x;

// read: x is: array length 3 of: array of: char
char[][3] x;

// read: x is: wchar indexed array of: ushort
ushort[wchar] x;

The only 'special' case in using the function and delegate types:

// read: x is: function taking float returning void
void function(float) x;

The quirk here is that the word function gets "read" before the parameter types... but otherwise the right-to-left thing holds very much true.  So as Tom said, you had written this:

// read: A is: array length 3 of: array length 2 of: float
float[2][3] A;

So the moral of the lesson?  Declerations of arrays index right-to-left, while expressions on arrays index left-to-right.  It seems odd at first, but there aren't any other details to it (that I'm aware of).

-- Chris Sauls