prettyPreAcc pp alvl wrap (Stencil2 sten bndy1 acc1 bndy2 acc2)
  = wrap 
  $ prettyArrOp "stencil2" [parens (prettyPreFun pp alvl sten),
                            prettyBoundary acc1 bndy1,
                            pp alvl parens acc1,
                            prettyBoundary acc2 bndy2,
                            pp alvl parens acc2]
prettyPreAcc pp alvl wrap (Stencil2 sten bndy1 acc1 bndy2 acc2)
  = wrap 
  $ prettyArrOp "stencil2" [parens (prettyPreFun pp alvl sten),
                            prettyBoundary acc1 bndy1,
                            pp alvl parens acc1,
                            prettyBoundary acc2 bndy2,
                            pp alvl parens acc2]
prettyPreAcc pp alvl wrap (Stencil2 sten bndy1 acc1 bndy2 acc2)
  = wrap 
  $ prettyArrOp "stencil2" [parens (prettyPreFun pp alvl sten),
                            prettyBoundary acc1 bndy1,
                            pp alvl parens acc1,
                            prettyBoundary acc2 bndy2,
                            pp alvl parens acc2]