ref-set needs its one set of parens, and the last thing in the ref-set call needs to be a function either (fn [x] ...) or a symbol for a var that holds a function
On Mon, Nov 24, 2008 at 2:30 PM, Brian Doyle <[EMAIL PROTECTED]> wrote: > Thanks Kevin, I will try using reduce instead. I would like to know what > I'm doing wrong with updating the ref for future reference. Thanks. > > On Mon, Nov 24, 2008 at 3:23 PM, Kevin Downey <[EMAIL PROTECTED]> wrote: >> >> I know you are asking about refs, but you might want to think about >> using reduce to walk the line-seq. the nature of reduce lets you have >> access to the line-seq, two lines at a time no need for a ref. >> >> On Mon, Nov 24, 2008 at 2:17 PM, Brian Doyle <[EMAIL PROTECTED]> >> wrote: >> > I am parsing a file and to compare the current line >> > with the previous line of the file. I am using line-seq >> > to go thru the file and I thought I would create a >> > ref to store the previous line. When I want to update >> > the previous line value I can't seem to do it. I've >> > never used refs before so I'm sure I'm doing something >> > very stupid. >> > >> > (defstruct line :lat :lon :name) >> > >> > (defn convert [file] >> > (let [prev-line (ref (struct line))] >> > (with-open [r (reader file)] >> > (doseq [l (line-seq r)] >> > (let [ps (split #"," l) >> > c-line (struct line (ps 0) (ps 1) (ps 2))] >> > (if (not= c-line @pre-line) >> > (do ; do stuff here then update pre-line >> > (dosync ref-set pre-line (apply struct line (vals >> > c-line))) >> > (println @pre-line)))))))) ; this prints out all nils >> > doesn't seem to work >> > >> > >> > >> > Sorry if this email is not formatted correctly. Something is wrong with >> > my >> > browser >> > currently typing in a textarea. Thanks. >> > >> > >> > >> > > >> > >> >> >> >> -- >> The Mafia way is that we pursue larger goals under the guise of >> personal relationships. >> Fisheye >> >> > > > > > -- The Mafia way is that we pursue larger goals under the guise of personal relationships. Fisheye --~--~---------~--~----~------------~-------~--~----~ 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 To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/clojure?hl=en -~----------~----~----~----~------~----~------~--~---