Multidimensional array

[monarch_dodra]

On Thursday, 4 July 2013 at 23:02:10 UTC, Jonathan M Davis wrote:
> On Friday, July 05, 2013 00:39:47 Oleksiy wrote:
>> Hi,
>> 
>> I'm new to the language and would appreciate if anybody could
>> clarify the following:
>> 
>> 1. What is the rationale behind "prefix declaration" of an 
>> array?
>> Using right-to-left order to declare an array and left-to-right
>> order to access elements seems confusing.
>
> Because the brackets are part of the type, and the type goes to 
> the left of
> the variable name. The fact that C put in on the right-hand 
> side is actually
> quite bizarre, but they also did nonsense like make it
> so that in this declaration
>
> int* p1, p2;
>
> p1 is an int*, whereas p2 is an int, which D fixed (in D, both 
> are int*).
>
> - Jonathan M Davis

Arguably, this all comes from C's "value centric" scheme. When 
you write (not the C-like placement of the *):

int *p, a;

It means: with *p and a, you get an int.

Ditto, when you write:
int arr[5];
It is written that way to reflect that usage is:
*p = arr[0];

As stated in the first question, it makes sense that way in the 
context of:
#define WIDTH = 10
#define HEIGHT = 5
int matrix[WIDTH][HEIGHT];
a = matrix[w][h];

I'm just saying that's the explanation for it. Once you have to 
start making the distinction between "array of pointers" and 
"pointer to array", then clearly, things start crumbling apart, 
and D's approach is simply better. I'm just saying, there *is* an 
historical reason for this, not just arbitrary stupidness.

The fact that in D, declaration and indexing is "reversed" is 
something I've truly never even noticed, since to me, naturally, 
declarations read right to left, then parsing is left to right. 
So no problem there.