Hi Tomek!
> In a CGI application I was gathering SQL statements I wanted to run in > the final transaction. Because I use haskelldb, it was most convenient > to use (Database -> IO ()) as the type of the statement or a group of > statements. In this representation concatenating two statement groups so > they are executed in sequence can be done with: > > concatStmts s1 s2 = \db -> s1 db >> s2 db > > My mistake was that I forgot about db and wrote: > > concatStmts s1 s2 = s1 >> s2 > > And it was accepted because I had the Monad instance for ((->) r) in > scope (from Control.Monad.Trans I guess)! Have you considered changing the statements to have type 'ReaderT Database IO ()'? Then (>>) actually does what you want. Pozdrawiam, Arie -- Always go along with the group, or someone may drop a sixteen-ton safe on you. - The Buddy Bears _______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
