Read a configuration file: Difference between revisions

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 =={{header|Clojure}}==
+Tested with Clojure 1.9.0
-{{Incorrect|Clojure|Makes no attempt to parse the configuration file of the task description.}}
+<lang clojure>(ns read-conf-file.core
-One simple approach would be to use the [https://github.com/edn-format/edn edn-format] instead of the task's proposed config file.  Example <tt>config.edn</tt>:
+  (:require [clojure.java.io :as io]
-<pre>; This is a config file in edn format
+            [clojure.string :as str])
-; Blank lines and lines beginning with a semicolon are ignored.
+  (:gen-class))
-{
-  :fullname "Foo Barber"
-  :favorite-fruit "banana"
-  :needs-peeling true
-; :seeds-removed false
-  :other-family ["Rhu Barber" "Harry Barber"]
-}
-</pre>
+(def conf-keys ["fullname"
-In Clojure we can read the config directly into a map in our program.
+                "favouritefruit"
-<lang clojure>(let [cfg (read-string (slurp "config.edn"))]
+                "needspeeling"
-  (clojure.pprint/pprint cfg))</lang>
+                "seedsremoved"
+                "otherfamily"])
+(defn get-lines
+  "Read file returning vec of lines."
+  [file]
+  (try
+    (with-open [rdr (io/reader file)]
+      (into [] (line-seq rdr)))
+    (catch Exception e (.getMessage e))))
+(defn parse-line
+  "Parse passed line returning vec: token, vec of values."
+  [line]
+  (if-let [[_ k v] (re-matches #"(?i)^\s*([a-z]+)(?:\s+|=)?(.+)?$" line)]
+    (let [k (str/lower-case k)]
+      (if v
+        [k (str/split v #",\s*")]
+        [k [true]]))))
+(defn mk-conf
+  "Build configuration map from parsed lines."
+  [lines]
+  (->> (map parse-line lines)
+       (filter (comp not nil?))
+       (reduce (fn
+                 [m [k v]]
+                 (assoc m k v)) {})))
+(defn output
+  [conf-keys conf]
+  (doseq [k conf-keys]
+    (let [v (get conf k)]
+      (if v
+        (println (format "%s = %s" k (str/join ", " v)))
+        (println (format "%s = %s" k "false"))))))
+(defn -main
+  [filename]
+  (output conf-keys (mk-conf (get-lines filename))))</lang>
 {{out}}
+<pre>
-<pre>{:fullname "Foo Barber",
+fullname = Foo Barber
- :favorite-fruit "banana",
+favouritefruit = banana
- :needs-peeling true,
+needspeeling = true
- :other-family ["Rhu Barber" "Harry Barber"]}</pre>
+seedsremoved = false
+otherfamily = Rhu Barber, Harry Barber
+</pre>
 =={{header|Common Lisp}}==