Refactor generic functions to separate utils namespace, finaly bump version

project.clj

@@ -1,4 +1,4 @@
-(defproject rss-thread-watch "0.1.0-SNAPSHOT"
+(defproject rss-thread-watch "0.3.0-SNAPSHOT"
   :description "RSS based thread watcher"
   :url "http://example.com/FIXME"
   :license {:name "AGPL-3.0-only"

src/rss_thread_watch/feed_generator.clj

@@ -18,15 +18,12 @@
             [ring.util.response :as response]
             [clj-rss.core :as rss]
             [clojure.string :as s]
-            [rss-thread-watch.watcher :as watcher])
+            [rss-thread-watch.watcher :as watcher]
+            [rss-thread-watch.utils :as ut])
   (:gen-class))
 
 
-(defn indices
+
-  ;; https://stackoverflow.com/questions/8641305/find-index-of-an-element-matching-a-predicate-in-clojure
-  "Returns indexes of elements passing predicate"
-  [pred coll]
-   (keep-indexed #(when (pred %2) %1) coll))
 
 (defn new-guid-always
   "Generates always unique GUID for Feed item.
@@ -56,7 +53,7 @@
   (let [time-of-generation @watcher/time-of-cache
         guid-fn (if repeat? (fn [x] (new-guid-always x time-of-generation))
                     update-only-guid)
-        cache-start-index (first (indices (fn [x] (>= (:chod x) chod-treshold))
+        cache-start-index (first (ut/indices (fn [x] (>= (:chod x) chod-treshold))
                                           cache))
         ;; So we don't have to search thru everything we have cached
         needed-cache-part (subvec cache cache-start-index)

src/rss_thread_watch/utils.clj

@@ -0,0 +1,41 @@
+(ns rss-thread-watch.utils
+  "Util functions"
+  (:gen-class))
+;; ===== Generic functions ====
+
+(defn indices
+  ;; https://stackoverflow.com/questions/8641305/find-index-of-an-element-matching-a-predicate-in-clojure
+  "Returns indexes of elements passing predicate"
+  [pred coll]
+   (keep-indexed #(when (pred %2) %1) coll))
+
+;; ===== Macros =====
+(defmacro nil?-else
+  "Return x unless it's nil, the return y"
+  [x y]
+  `(let [result# ~x]
+        (if (nil? result#)
+          ~y
+          result#)))
+
+(defmacro when-else
+  "Evaluates tst, if it's true returns it's result.
+   If it's not, return else"
+  [tst else]
+  `(let [res# ~tst]
+     (if res#
+       res#
+       ~else)))
+
+(defmacro ret=
+  "compares two values using [=]. If the result is true
+   returns the value, else the result of [=].
+
+   Usefull with if-else"
+  [x y]
+  `(let [x# ~x
+         y# ~y
+         result# ~(= x y)]
+     (if result#
+       ~x
+       result#)))