Hi all, Below my .sig is a little Persist/Esqueleto program that works correctly. The getUserCount function does thr right thing and returns the number of rows in the User table. However, what I'd like is a generic function that returns the row count of any table, something vaguely like this: queryRowCount :: tableType -> SqlPersist IO Int64 queryRowCount tableName = do [Value x] <- select . from $ \(_ :: SqlExpr (Entity tableName)) -> return countRows return x Is there any way to do this? Its probably possible in Agda, but can it be made to work with GHC? Cheers, Erik -- ---------------------------------------------------------------------- Erik de Castro Lopo http://www.mega-nerd.com/ {-# LANGUAGE FlexibleContexts, GADTs, GeneralizedNewtypeDeriving, OverloadedStrings, QuasiQuotes, ScopedTypeVariables, TypeFamilies, TemplateHaskell #-} import Control.Monad (void) import Control.Monad.IO.Class (liftIO) import Database.Esqueleto import Database.Persist.Sqlite import Database.Persist.TH import GHC.Int (Int64) share [mkPersist sqlSettings, mkMigrate "migrateAll"] [persist| User firstName String lastName String emailAddress String UserName firstName lastName deriving Show Project name String description String deriving Show |] -- This works, but only for the User table. queryUserCount :: SqlPersist IO Int64 queryUserCount = do [Value x] <- select . from $ \(_ :: SqlExpr (Entity User)) -> return countRows return x main :: IO () main = withSqliteConn ":memory:" $ runSqlConn $ do void $ runMigrationSilent migrateAll void $ insert $ User "Fred" "Smith" "" void $ insert $ User "Johne" "Jones" "" void $ insert $ User "Paul" "Peters" "" queryUserCount >>= \c -> liftIO $ putStrLn $ "queryUserCount => " ++ show c