Re: technology discussion → does the world need a "new" C ?

On 10/07/2024 07:38, James Kuyper wrote:

On Sat, 6 Jul 2024 19:53:56 +0100, bart wrote:
 

On 06/07/2024 19:28, James Kuyper wrote:
>

... an expression that has type "array of type" is
converted to an expression with type "pointer to type" that points to
the initial element of the array object ..." (6.3.2.1p3).

>
This is really, really pedantic. Even gcc doesn't get it right in that
case, because if I try and compile this:
>
      int a, b>      a[b];
>
it says:
>
    error: subscripted value is neither array nor pointer nor vector

 There is no expression that has the type "array of type" in the above
code. How is that relevant to what I wrote?
 For the subscript operator:
"One of the expressions shall have type "pointer to complete object
type", the other expression shall have integer type," (6.5.2.1p1)
 Neither a nor b has the type "pointer to complete object type". Both a
and b have the type 'int'. How did you expect that code to be meaningful?
 Note that a[&b] would be valid, since &b is treated for this purpose as
a pointer to the first element of a 1-element array.
 Note that the standard doesn't mandate which expression have the pointer
type; that's because a[&b] is defined as *(a + &b), and you can add a
pointer to an integer in either order, so you can subscript an array as
array[5] or 5[array].
 

'Subscripting' I think we can agree is the same thing as 'indexing':
what those funny square brackets do.

 I can agree that subscripting is indeed what those square brackets do.
The C standard never mentions indexing, but I do agree that there is a
correspondence. However, if you derive any conclusions from that
correspondence that contradict what the C standard says about
subscripting, those conclusions are invalid.

My post was about what gcc says. Your point I believe was about the fact that indexing / subscripting can only be meaningful with a pointer type, according to C, and not an 'array' or 'vector'.
But gcc does mention subscripting in connection with arrays and vectors.
So /my/ point is that sometimes it is helpful not to be so strict if it helps understanding.