Hello, I have a bunch of little database IO functions. Each does something to the database, and returns a log string describing what it did, and possibly a meaningful result from the database. query :: IO (String, a) update :: a -> IO (String, ()) ...and a few functions that orchestrate all the little functions into doing useful work. syncWeek :: Week -> IO () syncAll : : IO () I don't want the individual functions to know what is done with the log string describing what they did. Top-level orchestrating functions should make that decision, which can be one of: 1) Collect and print all to a log once all computations are done. 2) Print to stdout *as each computation is run*. 3) Ignore them. Here is my understanding of how common monads would handle these requirements: Writer: 1 and 3 are easy. This is what I originally attempted to use, but I couldn't figure out how to accomplish #2. Reader: 2 and 3 can be accomplished if each function reads a shouldLog config variable from the reader and does a putStrLn depending on the value. Very ugly, as now each function has to know how to log output. State: Not sure, but the Writer docs in the transformers package points to this monad as maybe solving requirement #2 above. The use case is that when I call the top-level functions from a command line script, I want to see logging happening in real-time to stdout, but I may call the same top-level functions from a larger application that may be logging to somewhere other than stdout, and may call the top-level functions from yet another larger application which doesn't want anything to be logged. How can I glue together a bunch of smaller computations, which may call each other, and decide at a higher level what to do with the logging result of each computation? Seems like a perfect fit for Writer, except for the requirement to be able to print to stdout at each step. Bryan Vicknair