in reply to Re^3: Perl6 Contest #2: P6 That Doesn't Look Like P5
in thread Perl6 Contest #2: P6 That Doesn't Look Like P5

I took a rather different approach to the code. I love OO so i went that route.

#!/usr/bin/pugs
use v6;

class MultiCounter {
      has @.positions is rw;
      has @.lengths   is rw;
      submethod BUILD() { @.positions = (0) xx (@.lengths.end + 1); }
      method inc () returns Bool {
        @.positions[-1]++;
        for reverse (0..@.lengths.end - 1) -> $i {
         if (@.positions[$i + 1] > @.lengths[$i + 1]) {
            @.positions[$i]++;
            @.positions[$i + 1] = 0;
         }
        }
        
        return (@.positions[0] > @.lengths[0]) ?? 0 :: 1;             
      }                
}

class NestedLoops {
      has @.loops is rw;
      has MultiCounter $.counter is r;
      submethod BUILD() {
          $.counter = MultiCounter.new( :lengths( @.loops.map:{.end } 
+) );
      }
      method inc () returns Bool { $.counter.inc;  }
      method data () {
          my @data;
          for (0..@.loops.end) -> $i {
              push @data, @.loops[ $i ][$.counter.positions[$i]];
          }
          return @data;
      };
}

my $counter = NestedLoops.new( :loops(['a','b'],[0..2], ['one',2,3]) )
+;
while ($counter.inc) {
    $counter.data.join(" ").say;
}

[download]

Some refinements and added features would probably be good but this is my start.


___________
Eric Hodges

Replies are listed 'Best First'.
Re^5: Perl6 Contest #2: P6 That Doesn't Look Like P5
by eric256 (Parson) on Jun 03, 2005 at 18:04 UTC

    Some changes. Using invocants, and method dispatching based on signatures and a better data method.

    #!/usr/bin/pugs
use v6;

class MultiCounter {
      has @.positions is rw;
      has @.lengths   is rw;
      submethod BUILD() { @.positions = (0) xx (@.lengths.end + 1); }
      method inc () returns Bool {
        @.positions[-1]++;
        for reverse (0..@.lengths.end - 1) -> $i {
         if (@.positions[$i + 1] > @.lengths[$i + 1]) {
            @.positions[$i]++;
            @.positions[$i + 1] = 0;
         }
        }
        return (@.positions[0] > @.lengths[0]) ?? 0 :: 1;             
      }                
}

class NestedLoops {
      has @.loops is rw;
      has MultiCounter $.counter is r;
      submethod BUILD($self:) {
          $self.reset;
      }
      method reset () {
          $.counter = MultiCounter.new( :lengths( @.loops.map:{.end } 
+) );
      }
      method iter () returns Bool { $.counter.inc;  }
      method iter ($self: Code $code) {
             while ($self.iter) { $code($self.data) };
             $self.reset;
      }
      method data () {
          return map -> $i { @.loops[$i][ $.counter.positions[$i] ] } 
+0 .. @.loops.end;
      };
}

my $counter = NestedLoops.new( :loops(['a','b'],[0..2], ['one',2,3]) )
+;

$counter.iter( sub { say "HERE " ~ @_ } );
while ($counter.iter) { $counter.data.join(" ").say; }

    [download]

    ___________
    Eric Hodges
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