Solutions to the excercises

• List functions as catas: two are length, (++): thesis p. 26
• Cata on List, Tree: Thesis p. 25, 29
• A possible definition of anaList is the Haskell List library function unfoldr: anaList = List.unfoldr

  unfoldr :: (b->Maybe (a,b)) -> b -> [a]
  unfoldr f b  = case f b of Nothing    -> []
                             Just (a,b) -> a : unfoldr f b
  

• Zip as ana in Haskell
• Fusion: thesis p. 26 + similar to proof on p. 27
• PairList in Haskell, and in PairList in PolyP (PolyP output)
• depth = cata (maximum . (0:) . map (1+) . fl_rec)
• Thesis p. 69:

    flatten' = comp . pmap (:)
    comp     = crush (.) id