Hi Eugene You can store different things in a Map by collecting them with a simple 'sum' type:
import qualified Data.Map as Map
type DateTime = String -- just String for now.. type URL = String type UniqueID = String
Here's the sum type:
data LogData = LastLogin DateTime | LastLogout DateTime | ReferringURL URL deriving (Eq, Show)
type ExtraInfo = Map.Map UniqueID [LogData]
addData :: UniqueID -> LogData -> ExtraInfo -> ExtraInfo addData uid prop infos = case Map.lookup uid infos of Nothing -> Map.insert uid [prop] infos Just xs -> Map.insert uid (prop:xs) infos
Note - this stores all the LastLogin's ReferringURLS etc. As the list is LIFO the first @LastLogin@ in the list will be the latest one. If you don't like storing multiples, you could instead recast LogData as a record rather than sum type, but you then have to account for 'missing' data with Maybe's.
data LogData2 = LogData2 { last_login :: Maybe DateTime , last_logout :: Maybe DateTime , referring_URL :: Maybe URL }
emptyLogData2 :: LogData2 emptyLogData2 = LogData2 Nothing Nothing Nothing
type ExtraInfo_ALT = Map.Map UniqueID LogData2
addLastLogin :: UniqueID -> DateTime -> ExtraInfo_ALT -> ExtraInfo_ALT addLastLogin uid lasttime infos = case Map.lookup uid infos of Nothing -> Map.insert uid (emptyLogData2 { last_login = Just lasttime}) infos Just ld2 -> Map.insert uid (ld2 { last_login = Just lasttime}) infos
Make similar functions for last_logout, referring_url. Best wishes Stephen