Re: string manipulation

[Jeffrey Carter <jrcarter@acm.org>]

Gep wrote:
> 
>  while not valid
> loop
>  get_line(V_string, V_length);
> 
>  if V_length= V_string'length then
>       Skip_Line;
>       Valid := True;
>  else
>      valid :=false;
>      Put("invalid");
>  end if;
> end loop;

This looks better then that other code. You can do this. It will 
repeatedly get a line until it gets one that is exactly V_String'Length 
characters. If that's what you want. I don't see what it has to do with 
declaring a string variable of a specific length.

Valid is sort of useless here, as well as providing an opportunity for 
errors. You can forget to assign to it, or assign the wrong value. I 
think this would read better without it:

loop
    Get_Line (...);

    if V_Length = V_String'Length then
       Skip_Line;

       exit;
    end if;

    Put ("invalid");
end loop;

The purpose of the code is to exit the loop when a line of the right 
length is read. It's better for the code to say that, then to hide it 
behind a Boolean flag.

-- 
Jeff Carter
"Pray that there's intelligent life somewhere up in
space, 'cause there's bugger all down here on earth."
Monty Python's Meaning of Life