On Wed, 25 May 2005, Rob Kinyon wrote: > (This post references the discussion at > http://www.perlmonks.org/?node_id=458728, particularly dragonchild's > response at the bottom.) > > For those who don't know, cribbage is a game where each player has > access to 4 cards, plus a community card. Various card combinations > score points. The one in question is when cards add up to 15. If you > have a group of cards that add up to 15, you receive 2 points. This is > for every group, so if you have a ten and 2 fives, you get 4 points. > Two tens and two fives is 8 points. Face cards are worth 10 and aces > are 1, for these purposes. > > I proposed the following: > > # Fifteens > $score += 2 * all( 15 == [EMAIL PROTECTED] any( 0 .. 4 ) } ); > > * Is this syntax legal?

I think so. > * Does it do what I want it to do? Definitely not. It looks like you are thinking of junctions in terms of arrays, instead of scalar quantum superpositions. any( 0 .. 4 ) This returns a scalar junction of the five values (0,1,2,3,4). What you want is clearly all possible subsets of 0..4. You probably should write a coroutine to generate a lazy list of them. @hand{ $junction } returns a scalar junction of the five cards in the hand. Junctions auto-thread through operators, including postcircumfixes. [+] $junction returns $junction, since [+] $scalar == $scalar. The individual values auto-thread through. 15 == $junction This returns a junction of booleans. Knowing the possible values of @hand, all of them are false. all( $junction ) I'm not real good with nested junctions... 2 * $junction This returns another junction, with all elements doubled. (still zeros) You obviously want 2 * <junction>.elems, but I'm not sure if junctions support that method. $score += $junction Again this will make $score a junction of values. It will not add each of the junction values to $score. You probably want something like C< $score >>+=<< $junction.values > but that is another indication that you should be using arrays instead of junctions. And I'm not sure about the object interface to junctions anyway. > * Is there another way? Assuming you write the subset coroutine above, how about $score += ( subsets(0..4) ==> map { 2 * (15 == [+] @[EMAIL PROTECTED]) } ==> [+] ) ~ John Williams