To add some further clarification to the style hints suggested: many of us read code in multiple languages, and using formatting that is idiomatic to the language being used helps us keep the rules straight. f(a b) is an algol family syntax, the lisp family has a direct equivalent of (f a b), when you type out (f a (g b)) in a lisp as (f a(g b)) you cause many readers to do a double take, because it looks like an algol family function invocation on a (which is not being invoked as a function in our lisp syntax). Similar issues with camelCase versus kabob-case - If things are named unconventionally I have to slow down and double check whether the thing in question is really a method or a function (because they follow very different rules). And the same with trailing parenthesis - this is standard idiom in algol family languages, but when included in lisp family code, I have to slow down and consciously read it as lisp, rather than automatically knowing which I am seeing based on the paren placement.
On Friday, December 6, 2013 5:30:57 AM UTC-8, Justin Smith wrote: > > Parenthesis call the thing they wrap as a function. You have getConnection > wrapped in a redundant set of parenthesis, so the return value of > getConnection is being called. It is not a function, but it is a > ConnectionCustom, so you get your error. > > Some hints to make clojure code more readable: > > classes should be CamelCase, methods should be camelCase, functions should > be kabob-case. > > parens should be separated by a preceding item by a space - (f (g x)) - g > and x are not args to f, (g x) is the arg to f > > no line should contain only parens > > On Friday, December 6, 2013 5:08:23 AM UTC-8, Avinash Dongre wrote: >> >> Hi >> I have our own jdbc driver when I am trying to use clojure java.jdbc it >> is giving me error like below >> >> Exception in thread "main" java.lang.ClassCastException: >> a.b.my_custom_driver cannot be cast to clojure.lang.IFn >> at clojure.gemfireXD.jdbc$createStatement.invoke(client.clj:13) >> at clojure.gemfireXD.jdbc$eval13.invoke(client.clj:18) >> at clojure.lang.Compiler.eval(Compiler.java:6619) >> at clojure.lang.Compiler.load(Compiler.java:7064) >> at clojure.lang.Compiler.loadFile(Compiler.java:7020) >> at clojure.main$load_script.invoke(main.clj:294) >> at clojure.main$script_opt.invoke(main.clj:356) >> at clojure.main$main.doInvoke(main.clj:440) >> at clojure.lang.RestFn.invoke(RestFn.java:408) >> at clojure.lang.Var.invoke(Var.java:415) >> at clojure.lang.AFn.applyToHelper(AFn.java:161) >> at clojure.lang.Var.applyTo(Var.java:532) >> at clojure.main.main(main.java:37) >> >> >> When I tried following >> >> >> >> (ns clojure.custom.jdbc >> (:import [java.sql Connection DriverManager]) >> (:require [clojure.string :as clojure-string])) >> >> (defn getConnecton >> [url] >> (clojure.lang.RT/loadClassForName "custom.url.ClientDriver") >> (DriverManager/getConnection url)) >> >> (defn createStatement >> [db] >> (^Statement (.createStatement db) >> )) >> >> >> (createStatement((getConnecton "jdbc:mydbServer://localhost:1527/"))) >> >> Exception in thread "main" java.lang.ClassCastException: >> my.custom.implementation.internal.ConnectionCustom cannot be cast to >> clojure.lang.IFn >> at clojure.gemfireXD.jdbc$eval13.invoke(client.clj:16) >> at clojure.lang.Compiler.eval(Compiler.java:6619) >> at clojure.lang.Compiler.load(Compiler.java:7064) >> at clojure.lang.Compiler.loadFile(Compiler.java:7020) >> at clojure.main$load_script.invoke(main.clj:294) >> at clojure.main$script_opt.invoke(main.clj:356) >> at clojure.main$main.doInvoke(main.clj:440) >> at clojure.lang.RestFn.invoke(RestFn.java:408) >> at clojure.lang.Var.invoke(Var.java:415) >> at clojure.lang.AFn.applyToHelper(AFn.java:161) >> at clojure.lang.Var.applyTo(Var.java:532) >> at clojure.main.main(main.java:37) >> >> >> What I am missing here. >> > -- -- 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 --- You received this message because you are subscribed to the Google Groups "Clojure" group. To unsubscribe from this group and stop receiving emails from it, send an email to clojure+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out.
