Add type signatures and extension in code

Fixes #71

Database/MongoDB.hs

@@ -1,42 +1,54 @@
-{- |
+-- |
-Client interface to MongoDB database management system.
+-- Client interface to MongoDB database management system.
-
+--
-Simple example below. Use with language extensions /OverloadedStrings/ & /ExtendedDefaultRules/.
+-- Simple example below. 
-
+--
-
+-- @
-> import Database.MongoDB
+-- {\-\# LANGUAGE OverloadedStrings \#\-}
-> import Control.Monad.Trans (liftIO)
+-- {\-\# LANGUAGE ExtendedDefaultRules \#\-}
->
+-- 
-> main = do
+-- import Database.MongoDB
->    pipe <- connect (host "127.0.0.1")
+-- import Control.Monad.Trans (liftIO)
->    e <- access pipe master "baseball" run
+-- 
->    close pipe
+-- main :: IO ()
->    print e
+-- main = do
->
+--    pipe <- connect (host \"127.0.0.1\")
-> run = do
+--    e <- access pipe master \"baseball\" run
->    clearTeams
+--    close pipe
->    insertTeams
+--    print e
->    allTeams >>= printDocs "All Teams"
+-- 
->    nationalLeagueTeams >>= printDocs "National League Teams"
+-- run :: Action IO ()
->    newYorkTeams >>= printDocs "New York Teams"
+-- run = do
->
+--    clearTeams
-> clearTeams = delete (select [] "team")
+--    insertTeams
->
+--    allTeams >>= printDocs \"All Teams\"
-> insertTeams = insertMany "team" [
+--    nationalLeagueTeams >>= printDocs \"National League Teams\"
->    ["name" =: "Yankees", "home" =: ["city" =: "New York", "state" =: "NY"], "league" =: "American"],
+--    newYorkTeams >>= printDocs \"New York Teams\"
->    ["name" =: "Mets", "home" =: ["city" =: "New York", "state" =: "NY"], "league" =: "National"],
+-- 
->    ["name" =: "Phillies", "home" =: ["city" =: "Philadelphia", "state" =: "PA"], "league" =: "National"],
+-- clearTeams :: Action IO ()
->    ["name" =: "Red Sox", "home" =: ["city" =: "Boston", "state" =: "MA"], "league" =: "American"] ]
+-- clearTeams = delete (select [] \"team\")
->
+-- 
-> allTeams = rest =<< find (select [] "team") {sort = ["home.city" =: 1]}
+-- insertTeams :: Action IO [Value]
->
+-- insertTeams = insertMany \"team\" [
-> nationalLeagueTeams = rest =<< find (select ["league" =: "National"] "team")
+--    [\"name\" =: \"Yankees\", \"home\" =: [\"city\" =: \"New York\", \"state\" =: \"NY\"], \"league\" =: \"American\"],
->
+--    [\"name\" =: \"Mets\", \"home\" =: [\"city\" =: \"New York\", \"state\" =: \"NY\"], \"league\" =: \"National\"],
-> newYorkTeams = rest =<< find (select ["home.state" =: "NY"] "team") {project = ["name" =: 1, "league" =: 1]}
+--    [\"name\" =: \"Phillies\", \"home\" =: [\"city\" =: \"Philadelphia\", \"state\" =: \"PA\"], \"league\" =: \"National\"],
->
+--    [\"name\" =: \"Red Sox\", \"home\" =: [\"city\" =: \"Boston\", \"state\" =: \"MA\"], \"league\" =: \"American\"] ]
-> printDocs title docs = liftIO $ putStrLn title >> mapM_ (print . exclude ["_id"]) docs
+-- 
->
+-- allTeams :: Action IO [Document]
--}
+-- allTeams = rest =<< find (select [] \"team\") {sort = [\"home.city\" =: 1]}
+-- 
+-- nationalLeagueTeams :: Action IO [Document]
+-- nationalLeagueTeams = rest =<< find (select [\"league\" =: \"National\"] \"team\")
+-- 
+-- newYorkTeams :: Action IO [Document]
+-- newYorkTeams = rest =<< find (select [\"home.state\" =: \"NY\"] \"team\") {project = [\"name\" =: 1, \"league\" =: 1]}
+-- 
+-- printDocs :: String -> [Document] -> Action IO ()
+-- printDocs title docs = liftIO $ putStrLn title >> mapM_ (print . exclude [\"_id\"]) docs
+--
+-- @
+--
 
 module Database.MongoDB (
     module Data.Bson,