Re: eliminating array bounds checking overhead

mayur_naik@my-deja.com writes:
> Does any language or any machine provide some mechanism to:
>
> 1. index an array without checking its bounds
> 2. throw an exception if the index was actually out of range
> 3. allow the programmer to catch and handle the exception rather than
> terminate the program


Well, Ada does. The strong typing gives information to the compiler for it to
deduce when range checking is not needed:


declare
    subtype Index is Integer range 1..10;
    type Arr is array (Index) of Integer;
    a : Arr;
    element : Integer;
    j : Index := 1;
    k : Integer := 11;
begin
    for i in a'Range loop
        element := a(i); -- no range checking needed, i is in range by definition
    end loop;
    a(j); -- range checking not needed, j is within Index by definition
    a(k); -- range checking needed due possibility of k being outside of Index
exception
    when Constraint_Error =>
          -- process the out-of-range error from a(k)
end;


--
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                                                                                              The Rhythm has control.
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