Refactor into separate namespaces.

project.clj

@@ -6,5 +6,5 @@
   :dependencies [[org.clojure/clojure "1.5.1"]
                  [clj-http "0.7.0"]
                  [cheshire "5.0.2"]]
-  :plugins [[lein-midje "3.0.0"]]
+  :plugins [[lein-midje "3.0.0"] [lein-kibit "0.0.8"]]
   :main foreclojure-downloader.core)

src/foreclojure_downloader/api.clj

@@ -0,0 +1,15 @@
+(ns foreclojure-downloader.api
+  (:require [clj-http.client :as client])
+  (:use [slingshot.slingshot :only [try+]]))
+
+(defn- problem-url
+  "Return the 4clojure URL for a given problem number."
+  [n]
+  (str "http://www.4clojure.com/api/problem/" n))
+
+(defn problem
+  "Returns a numbered problem from 4clojure as a map."
+  [n]
+  (try+ (assoc (:body (client/get (problem-url n) {:as :json})) :number n)
+        (catch [:status 404] _)))
+

src/foreclojure_downloader/core.clj

@@ -1,73 +1,13 @@
 (ns foreclojure-downloader.core
-  (:require [clojure.string :as string])
-  (:require [clojure.core.reducers :as reducers])
-  (:require [clj-http.client :as client])
-  (:require [cheshire.core :as cheshire]))
+  (:require [foreclojure-downloader.api :as api]
+            [foreclojure-downloader.writer :as writer]))
 
-(defn download-problem [n]
-  "Download the given problem number from 4clojure."
-  (let [url (str "http://www.4clojure.com/api/problem/" n)
-        response (client/get url {:throw-exceptions false})]
-    (when (= 200 (:status response))
-      (cheshire/parse-string (:body response) true))))
-
-(defn convert-newlines [string]
-  (string/replace string "\r\n" "\n"))
-
-(defn parse-test [test]
-  "Take a String test and parse out the equality operator and two sides.
-
-  Do this with a regular expression rather than read-string in an attempt
-  to preserve the original test code: e.g. reading #(* % 2) with
-  read-string produces (fn* [pn_1234#] (* pn_1234# 2))."
-  (if-let [matches (re-find #"^(?s)\((==?)\s+(#?\".+\"|'?\(.+\)|\[.+\]|#?\{.+\}|\S+)\s+(#?\".+\"|'?\(.+\)|\[.+\]|#?\{.+\}|\S+)\)$"
-                            (convert-newlines test))]
-    matches
-    ["" "=" (convert-newlines test) true]))
-
-(defn arrow [test]
-  "Return the appropriate checker for the given test."
-  (let [equals (second (parse-test test))]
-    (str equals ">")))
-
-(defn lhs [test]
-  "Return the left-hand side of the given test."
-  (nth (parse-test test) 2))
-
-(defn rhs [test]
-  "Return the left-hand side of the given test."
-  (last (parse-test test)))
-
-(defn checker [test]
-  "Return the full checker for the given test."
-  (str "  " (lhs test) " " (arrow test) " " (rhs test)))
-
-(defn checkers [problem]
-  "Return all checkers for the given problem."
-  (str (string/join "\n" (map checker (:tests problem))) ")"))
-
-(defn fact [problem]
-  "Return a full fact block for a given problem including all checkers."
-  (str "(future-fact \"" (:title problem) "\"\n" (checkers problem) "\n"))
-
-(defn problem-file-content [n problem]
-  "Return the full test file content for a given problem."
-  (str "(ns foreclojure-solutions.p" n "\n"
-       "  (:use midje.sweet))\n"
-       "\n"
-       "(defn __ []\n"
-       "  \"Implement me!\")\n"
-       "\n"
-       (fact problem)))
-
-(defn problem-file-name [n]
-  (str "src/foreclojure_solutions/p" n ".clj"))
-
-(defn write-problem [n]
-  (when-let [problem (download-problem n)]
-    (.mkdirs (java.io.File. "src/foreclojure_solutions"))
-    (spit (problem-file-name n) (problem-file-content n problem)))
-    n)
+(defn- problems
+  []
+  (pmap api/problem (range 1 200)))
 
 (defn -main []
-  (into [] (reducers/map write-problem (range 1 200))))
+  (do
+    (println "Downloading problems...")
+    (pmap writer/write-problem (problems))
+    nil))

src/foreclojure_downloader/translator.clj

@@ -0,0 +1,41 @@
+(ns foreclojure-downloader.translator
+  (:require [clojure.string :as string]))
+
+(defn- parse-simple-test
+  "Parse simple tests of the form (= x y) where possible."
+  [test]
+  (next (re-find #"^(?s)\((==?)\s+(#?\".+\"|'?\(.+\)|\[.+\]|#?\{.+\}|\S+)\s+(#?\".+\"|'?\(.+\)|\[.+\]|#?\{.+\}|\S+)\)$"
+                 test)))
+
+(defn- test->checker
+  "Translate a test into a Midje checker.
+
+  Tests of the form (= x y) will be translated to x => y but more complex tests
+  will be preserved and checked to be true, e.g. (and (= x y) (= z a)) => true"
+  [test]
+  (let [normalized-test (string/replace test "\r\n" "\n")]
+    (if-let [[equals left right] (parse-simple-test normalized-test)]
+      (str "  " left " " equals "> " right)
+      (str normalized-test " => true"))))
+
+(defn- checkers
+  "Return all checkers for the given problem."
+  [problem]
+  (str (string/join "\n" (map test->checker (:tests problem))) ")"))
+
+(defn- fact
+  "Return a full fact block for a given problem including all checkers."
+  [problem]
+  (str "(future-fact \"" (:title problem) "\"\n"
+       (checkers problem) "\n"))
+
+(defn problem-test
+  "Return the full test for a given problem as a String."
+  [problem]
+  (str "(ns foreclojure-solutions.p" (:number problem) "\n"
+       "  (:use midje.sweet))\n"
+       "\n"
+       "(defn __ []\n"
+       "  \"Implement me!\")\n"
+       "\n"
+       (fact problem)))

src/foreclojure_downloader/writer.clj

@@ -0,0 +1,16 @@
+(ns foreclojure-downloader.writer
+  (:require [foreclojure-downloader.translator :as translator]))
+
+(defn- file-name
+  "Return the file name for the given problem."
+  [problem]
+  (str "src/foreclojure_solutions/p" (:number problem) ".clj"))
+
+(defn write-problem
+  "Write the given problem to disk."
+  [problem]
+  (do
+    (.mkdirs (java.io.File. "src/foreclojure_solutions"))
+    (spit (file-name problem) (translator/problem-test problem)))
+    problem)
+