On 28.05.2009, at 21:23, CuppoJava wrote: > eg. > (with_file "myfile.txt" > (write "asdf") > (close)) > > compared to. > (with_file "myfile.txt" > (fn [] > (write "asdf") > (close)))
For that kind of application, you might also want to use the state monad (see http://onclojure.com/2009/03/23/a-monad-tutorial-for- clojure-programmers-part-3/). You'd have your function (defn with-file [filename file-action] ...) whose file-action argument is a state-monad value, i.e. a function that takes the opened file as its argument and returns a result plus the same file object. The advantage of using the state monad is that you can compose the basic file actions (read, write, ...) into composite file actions. You could for example define a file action that reads a file in a specific format and returns the contents in a suitable data structure. Moreover, having the file object hidden in the state of state monad functions makes it very difficult to use the file incorrectly (i.e. assigning it to a var for later use). Konrad. --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Clojure" group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en -~----------~----~----~----~------~----~------~--~---
