Simple word translator taking advantage of Wikipedia

Question

This is my first Clojure script (simple word translator based on Wikipedia), and I guess there are things which could be simplified / done more idiomatic way. Specifically, I wonder if get-translations couldn't be done better (it produces map lang code => term form regexp sequence).

(ns wiki-translate
   (:require [clojure.contrib.http.agent :as h])
   (:require [clojure.contrib.string :as s])
   (:import (java.net URLDecoder URLEncoder))
)

(defn url-decode
  ([text] (URLDecoder/decode text "UTF-8"))
)

(defn url-encode
  ([text] (URLEncoder/encode text "UTF-8"))
)

(defn get-url
  ([lg term] (str "http://" lg ".wikipedia.org/wiki/" (url-encode term)))
)

(defn fetch-url
  ([url] (h/string (h/http-agent url)))
)

(defn get-translations
  ([cnt]  (apply sorted-map (flatten (for  [s (re-seq #"interwiki-([^\"]+).*wiki\/([^\"]+)\".*/a>" cnt)] [(s 1) (s 2)]))))
)

(defn translate
   ([term src-lg tgt-lg] (
    let [translations (get-translations (fetch-url (get-url src-lg term)))]
      (if (contains?  translations tgt-lg) (s/replace-str  "_" " " (url-decode (get translations tgt-lg))) "<NOT FOUND>")))
)

(defn prompt-read 
  ([] (prompt-read ""))
  ([prompt] (print (format "%s: " prompt)) (flush ) (read-line))
)

(defn prompt-translate
  ([] (let [src-lg (prompt-read "Source language (en, fr, de ...)") tgt-lg (prompt-read "Target language  (en, fr, de ...)") term (prompt-read "Term to translate")]
  (println (str "\"" term "\" translated from " src-lg " to " tgt-lg " : " (translate term src-lg tgt-lg)))))
)

(while true (prompt-translate))

Answer 1

Don't use the multiple-arity syntax for defn unless you actually need to:

(defn url-decode
  [text]
  (URLDecoder/decode text "UTF-8"))

Your code could use some line breaks here and there. This is how clojure is usually indented:

(defn translate
  [term src-lg tgt-lg]
    (let [translations (get-translations (fetch-url (get-url src-lg term)))]
      (if (contains?  translations tgt-lg)
        (s/replace-str  "_" " " (url-decode (get translations tgt-lg)))
      "<NOT FOUND>")))

and:

(defn prompt-translate
  []
  (let [src-lg (prompt-read "Source language (en, fr, de ...)")
        tgt-lg (prompt-read "Target language  (en, fr, de ...)")
        term (prompt-read "Term to translate")]
    (println (str "\"" term "\" translated from " src-lg " to " tgt-lg " : " (translate term src-lg tgt-lg)))))

Instead picking out the regexp groups by index, you should use destructuring:

(defn get-translations
  [cnt]
  (apply sorted-map
    (flatten
      (for  [[_ a b] (re-seq #"interwiki-([^\"]+).*wiki\/([^\"]+)\".*/a>" cnt)]
        [a b]))))

... or better yet, I think, would be to do something like this:

(defn get-translations
  [cnt]
  (apply sorted-map
    (mapcat
      rest
      (re-seq #"interwiki-([^\"]+).*wiki\/([^\"]+)\".*/a>" cnt))))