Card.isSpecial and isValid

1 files changed, 12 insertions, 0 deletions

diff --git a/Card.hs b/Card.hs
index 3ba3ce1..321df84 100644
--- a/Card.hs
+++ b/Card.hs
@@ -35,3 +35,15 @@ shuffle gen xs = (head right):(shuffle newGen (left ++ (tail right)))
     where (rand, newGen) = random gen
           i = rand `mod` (length xs)
           (left, right) = splitAt i xs
+
+-- | Check if card is special.
+isSpecial :: Card -> Bool
+isSpecial (Card _ rk)
+  | rk `elem` [Two, Three, Seven, Jack, Queen] = True
+  | otherwise = False
+
+-- | Check if `card` is valid after `prev`.
+isValid :: Card -> Card -> Bool
+isValid prev@(Card st' rk') card@(Card st rk) =
+    match && (not (isSpecial prev) || isSpecial card)
+        where match = (st == st') || (rk == rk')