so after being inspired by the continual excellent help here, i am trying my hand at writing a multiple replace using Useful.replace Useful.replace origStr pattStr replStr gives for Useful.replace "This original string" "orig" "very orig" "This very original string" what i want to do is something like multRepl origStr [patt1,patt2] [repl1,repl2] so we get from multRepl "This original string" ["orig","ing"] ["very orig","ucture"] "This very original structure" what i have come up with is: multRepl :: String -> [String] -> [String] -> [String] multRepl str ss rs = [U.replace str a b | (a,b) <- (zip ss rs)] this produces in 2 passes: ["This very original string","This very original structure"] to get the final result, i could just last multRepl but i would like to know if this is a good way to do things. i suppose going through the incremental steps is obligatory, but after printing out the result and seeing these steps, it feels like i'm producing throw away stuff - though perhaps that's just an illusion stemming from a similar function php5 has where you get the result without seeing anything behind the scenes. -- In friendship, prad ... with you on your journey Towards Freedom http://www.towardsfreedom.com (website) Information, Inspiration, Imagination - truly a site for soaring I's