Re: stopping a loop iteration without exiting it

[G. B. <nonlegitur@nmhp.invalid>]

Paul Rubin <no.email@nospam.invalid> wrote:
> "; as
> Mart van de Wege says, you could use GOTO for everything so none of it
> is needed.  The question is whether it improves code readability,
> reliability, developer productivity, etc.

Another question is what the alternative really is.
Having both read and written Perl text, I still find it 
more promising to start a filter written like this:

   loop
      Process (Line, Result => Classification);
      case Classification is
         when Throwaway =>
            null;
         when Hit =>
            Handle (Factory.Make (Input => Line));
         when Unclear =>
            Report (Line);
      end case;
      Get_Line (Line);
   end loop;

Subprogram Process then looks at a single line
of input, in a way that is similar to the pattern parts
of AWK programs. Actions are triggered by Handle
only.

Perl’s continue block has one noteworthy piece 
of design, I think. It allows expressing something 
that is going to happen each time around the loop
irrespective of the loop’s other control structure.
There doesn’t seem to be a way to express this
fact clearly in most languages, including Ada.
Conventions and idioms aren’t the same thing
as a special structure provided by the language.

 while (Conditions) {
   ...
 } continue {
   ...
 }

I am not convinced, though, that an uncontrollable 
iteration is a Good Thing.