Re: Recursion, Yo

On Sun, 14 Apr 2024 00:23:44 +0100
Ben Bacarisse <ben.usenet@bsb.me.uk> wrote:

Michael S <already5chosen@yahoo.com> writes:
 

On Sat, 13 Apr 2024 00:13:36 -0000 (UTC)
Lawrence D'Oliveiro <ldo@nz.invalid> wrote:
 

On Fri, 12 Apr 2024 14:35:47 +0200, Janis Papanagnou wrote:
 

It seems that's one of the fundamental differences between
(low-level) languages that want to provide such technical factors
explicit to the user and between languages that want to provide a
higher abstraction.
 
Algol 60, Pascal, Simula 67 and Algol 60, Eiffel, etc. all took
that approach.   

 
Pascal had explicit pointers, though. Algol 68 and Ada did not. 

>
Of course, Ada has pointers. The are called access types.
https://en.wikibooks.org/wiki/Ada_Programming/Types/access
>
I never learned Algol-68, but considering your reputation I'd want
to see confirmation from more reliable source. 

 
I suppose it all depends on what constitutes a pointer, but Algol 68
has pointers to this extent:
 
BEGIN
   INT i := 42;
   [3] INT a := (1, 2, 3);
 
   REF INT p := i;   CO p is a "pointer" to i
CO REF INT(p) := 99; CO changes i via p
CO p := a[2];        CO p now points to the second element of array a
CO REF INT(p) := 99; CO change that element via p
CO
 
   print((i, a[1], a[2], a[3]))
END
 
I'd call p a pointer.
 

Thank you.
It looks closer to C than to Pascal, i.e. pointer can point to any
object rather than just to dynamically allocated object.