[c.s.keywords] Improved support for ns-qualified keywords

See clojure-emacs/cider-nrepl#224.

src/compliment/sources/keywords.clj

@@ -1,7 +1,7 @@
 (ns compliment.sources.keywords
   "Completion for keywords interned globally across the application"
   (:require [compliment.sources :refer [defsource]]
-            [compliment.utils :refer [defmemoized]])
+            [compliment.utils :refer [defmemoized resolve-namespace]])
   (:import java.lang.reflect.Field))
 
 (defmemoized ^:private keywords-table
@@ -10,12 +10,38 @@
     (.setAccessible field true)
     (.get field nil)))
 
-(defn candidates
-  [prefix _ _]
-  (when (= (first prefix) \:)
+(defn qualified-candidates
+  "Returns a list of namespace-qualified double-colon keywords (like ::foo)
+  resolved for the given namespace."
+  [prefix ns]
+  (let [prefix (subs prefix 2)
+        ns-name (str ns)]
+    (for [[kw _] (keywords-table)
+          :when (= (namespace kw) ns-name)
+          :when (.startsWith (name kw) prefix)]
+      (str "::" (name kw)))))
+
+(defn aliased-candidates
+  "Returns a list of alias-qualified double-colon keywords (like ::str/foo),
+  where alias has to be registered in the given namespace."
+  [prefix ns]
+  (let [[_ alias prefix] (re-matches #"::([^/]+)/(.*)" prefix)
+        alias-ns-name (str (resolve-namespace (symbol alias) ns))]
     (for [[kw _] (keywords-table)
-          :when (.startsWith (str kw) (subs prefix 1))]
-      (str ":" kw))))
+          :when (= (namespace kw) alias-ns-name)
+          :when (.startsWith (name kw) prefix)]
+      (str "::" alias "/" (name kw)))))
+
+(defn candidates
+  [^String prefix, ns _]
+  (let [single-colon? (.startsWith prefix ":")
+        double-colon? (.startsWith prefix "::")
+        has-slash? (> (.indexOf prefix "/") -1)]
+    (cond (and double-colon? has-slash?) (aliased-candidates prefix ns)
+          double-colon? (qualified-candidates prefix ns)
+          single-colon? (for [[kw _] (keywords-table)
+                              :when (.startsWith (str kw) (subs prefix 1))]
+                          (str ":" kw)))))
 
 (defsource ::keywords
   :candidates #'candidates

test/compliment/sources/t_keywords.clj

@@ -14,4 +14,15 @@
     => (contains #{":compliment.sources.t-keywords/bar"
                    ":compliment.sources.t-keywords/baz"
                    ":compliment.sources.t-keywords/foo"}
-                 :gaps-ok)))
+                 :gaps-ok))
+
+  (fact "namespace-qualified keywords can be completed in the same namespace"
+    (do (str ::foo ::bar ::baz)
+        (src/candidates "::ba" *ns* nil))
+    => (contains #{"::bar" "::baz"} :gaps-ok))
+
+  (fact "namespace-qualified keywords can be completed with an ns alias"
+    (do (str :compliment.core/aliased-one :compliment.core/aliased-two)
+        (require '[compliment.core :as core])
+        (src/candidates "::core/ali" *ns* nil))
+    => (contains #{"::core/aliased-two" "::core/aliased-one"} :gaps-ok)))