files/practicum/BinTreeMapEnFold.icl

   1 module BinTreeMapEnFold
   2
   3 import StdEnv
   4
   5 :: BTree a                              = Tip a | Bin (BTree a) (BTree a)
   6
   7 testboom                                = Bin (Bin (Bin (Tip 1) (Tip 2)) (Tip 3)) (Bin (Bin (Tip 4) (Tip 5)) (Bin (Tip 6) (Bin (Tip 7) (Tip 8))))
   8
   9 mapbtree                                :: (a -> b) (BTree a) -> BTree b
  10 mapbtree f (Tip a)              = Tip (f a)
  11 mapbtree f (Bin t1 t2)  = Bin (mapbtree f t1) (mapbtree f t2)
  12
  13 foldbtree                               :: (a a -> a) (BTree a) -> a
  14 foldbtree f (Tip a)             = a
  15 foldbtree f (Bin t1 t2) = f (foldbtree f t1) (foldbtree f t2)
  16
  17 f1                                              :: // meest algemene type
  18 f1                                              = foldbtree (+)
  19
  20 f2                                              :: // meest algemene type
  21 f2                                              = foldbtree (+) o (mapbtree (const 1))
  22
  23 f3                                              :: // meest algemene type
  24 f3                                              = foldbtree (\x y -> 1 + max x y) o (mapbtree (const 0))
  25
  26 f4                                              :: // meest algemene type
  27 f4                                              = foldbtree (++) o (mapbtree (\x -> [x]))
  28
  29 Start :: (Int,Char,Int,Char,Int,Char,[Int],Char)
  30 Start = (f1 testboom, '\n'
  31         ,f2 testboom, '\n'
  32         ,f3 testboom, '\n'
  33         ,f4 testboom, '\n'
  34         )