-- | isnull (function null in original Haskell source) function identifier
-isnullId :: String
-isnullId = "isnull"
+nullId :: String
+nullId = "null"
-- | replace function identifier
copyId :: String
copyId = "copy"
+-- | copyn function identifier
+copynId :: String
+copynId = "copyn"
+
-- | map function identifier
mapId :: String
mapId = "map"