Man or boy test

[luben karavelov]

François Perrad wrote:
> Do you know the Knuth's "man or boy" test ?
> 
> If not, see http://en.wikipedia.org/wiki/Man_or_boy_test
> that contains explanations and implementations in various languages.
> 
> A Perl5 implementation is :
>      sub A {
>          my ($k, $x1, $x2, $x3, $x4, $x5) = @_;
>          my $B;
>          $B = sub {
>              return A(--$k, $B, $x1, $x2, $x3, $x4);
>          };
>          return &$x4() + &$x5() if ($k <= 0);
>          return &$B();
>      }
> 
>      print A(10, sub{1}, sub{-1}, sub{-1}, sub{1}, sub{0}), "\n";
>      # the expected result is -67
> 
> In r32377, I commit a Lua implementation that works on Parrot.
> 
> Can we do a Perl6 implementation with the current Rakudo ?
> 
> François.
> 
> _______________________________________________
> http://lists.parrot.org/mailman/listinfo/parrot-dev

Here it is, straight translation of the perl5 code:

sub A($k, $x1, $x2, $x3, $x4, $x5) {
     my $B = sub { A(--$k, $B, $x1, $x2, $x3, $x4) };
     $k <= 0 ?? $x4() + $x5() !! $B();
}

say A(10, sub{1}, sub{-1}, sub{-1}, sub{1}, sub{0} );

But it reaches max recursion limit for $k>3

luben