More minor repl improvements

src/ludus/repl.clj

@@ -15,6 +15,10 @@
 
 (def prompt "=> ")
 
+(defn- exit []
+  (println "\nGoodbye!")
+  (System/exit 0))
+
 (def base-ctx (merge prelude/prelude
                 {::repl true
                  "repl"
@@ -25,10 +29,19 @@
                   :flush
                   {:name "flush"
                    ::data/type ::data/clj
-                        :body (fn []
+                   :body (fn 
+                           ([]
                             (let [session @current-session]
                               (swap! session #(assoc % :ctx (volatile! base-ctx)))
-                                  :ok))}
+                              :ok))
+                           ([name]
+                            (if-let [session (get @sessions name)]
+                              (do
+                                (swap! session #(assoc % :ctx (volatile! base-ctx)))
+                                :ok)
+                              (do 
+                                (println "No session named" name)
+                                :error))))}
 
                   :new
                   {:name "new"
@@ -48,7 +61,13 @@
                                :ok)
                              (do
                                (println "No session named" name)
-                                    :error)))}}}))
+                               :error)))}
+
+                  :quit
+                  {:name "quit"
+                   ::data/type ::data/clj
+                   :body (fn [] (exit))}
+                  }}))
 
 (defn- new-session [name]
   (let [session (atom {:name name
@@ -57,27 +76,29 @@
     (swap! sessions #(assoc % name session))
     session))
 
-(defn- exit []
-  (println "\nGoodbye!")
-  (System/exit 0))
-
 (defn repl-loop []
   (let [session-atom @current-session
         session @session-atom
         orig-ctx (:ctx session)]
     (print (str (:name session) prompt))
     (flush)
-    (let [raw-input (read-line)
+    (let [raw-input (read-line)]
-          input (if raw-input raw-input (exit))
+      (cond
+        (= nil raw-input) (exit)
+
+        (= "" raw-input) (recur)
+
+        :else
+        (let [input (if raw-input raw-input (exit))
               parsed (-> input (scanner/scan) (parser/parse))
               {result :result ctx :ctx} (interpreter/interpret-repl parsed (:ctx session))]
           (if (= result ::interpreter/error)
-        (repl-loop)
+            (recur)
             (do
               (println (show/show result))
               (when (not (= @ctx @orig-ctx))
                 (swap! session-atom #(assoc % :ctx ctx)))
-          (repl-loop))))))
+              (recur))))))))
 
 (defn launch []
   (println "Welcome to Ludus (v. 0.1.0-alpha)")