prettyPreAcc pp alvl wrap (Scanr f e acc)
  = wrap 
  $ prettyArrOp "scanr" [parens (prettyPreFun pp alvl f), prettyPreExp pp 0 alvl parens e,
                         pp alvl parens acc]
prettyPreAcc pp alvl wrap (Scanr f e acc)
  = wrap 
  $ prettyArrOp "scanr" [parens (prettyPreFun pp alvl f), prettyPreExp pp 0 alvl parens e,
                         pp alvl parens acc]
prettyPreAcc pp alvl wrap (Scanr f e acc)
  = wrap 
  $ prettyArrOp "scanr" [parens (prettyPreFun pp alvl f), prettyPreExp pp 0 alvl parens e,
                         pp alvl parens acc]