binOpsMap :: [(String, BinOp)]
binOpsMap =
  [ ("+", Add), ("-", Sub), ("*", Mul), ("/", Div), ("equal?", Eq)
  , ("greater?", Gt), ("less?", Le) ]
binOpsMap :: [(String, BinOp)]
binOpsMap =
  [ ("+", Add), ("-", Sub), ("*", Mul), ("/", Div), ("equal?", Eq)
  , ("greater?", Gt), ("less?", Le) ]
binOpsMap =
  [ ("+", Add), ("-", Sub), ("*", Mul), ("/", Div), ("equal?", Eq)
  , ("greater?", Gt), ("less?", Le) ]