I am implementing Unix sort in Clojure. This is my first program, and I would like some feedback regarding any non-idiomatic, harmful code and any other best practices I can include in future versions. I tried my best to follow the coding standards, but went with camelCase instead of hyphen-case for variable and function names.
Main class: sort.core
(ns sort.core
(:gen-class)
(:use clojure.contrib.core)
(:use clojure.tools.cli)
(:require [sort.lib :as lib]))
(defn -main [& args]
(let [[options args banner] (cli args
["-h" "--help" "Show help" :default false :flag true]
["-i" "--input" "The input file" :default nil]
["-d" "--delim" "The delimitter" :default ","]
["-f" "--field" "The column to parse(1 indexed)" :parse-fn #(Integer. %)])
{:keys [delim field input]} options]
(lib/help options args banner)
(when (= (lib/fileKind input) "file")
(lib/printOutVector delim
(lib/sortVector field
(lib/splitFile input delim ))))
(System/exit 0)))
Library: sort.lib
(ns sort.lib
(:require [clojure.string :as str])
(:import java.io.File))
(defn splitFile
"splits a file into a 2d array"
[s delim]
(pmap #(str/split % (re-pattern delim))
(str/split(slurp s) #"\n")))
(defn printOutVector
"prints out the 2dVector formatted by the delim arg"
[delim coll]
(println
(apply str
(interpose "\n" (map #(apply str (interpose delim %)) coll)))))
(defn sortVector
"sorts a 2d vector by the given index"
[index coll]
(sort-by #(nth % index) coll))
(defn help
"custom help message for sort.core"
[opts args banner]
(when (:help opts)
(println (str "input: " (:input opts)))
(println (str "field: " (:field opts)))
(println (str "delim: " (:delim opts)))
(println banner)
(System/exit 0)))
(defn fileKind [filename]
(let [f (File. filename)]
(cond
(.isFile f) "file"
(.isDirectory f) "directory"
(.exists f) "other"
:else "(non-existent)" )))
