Stand up super basic repl

src/ludus/repl.clj

@@ -3,9 +3,40 @@
     [ludus.scanner :as scanner]
     [ludus.parser :as parser]
     [ludus.interpreter :as interpreter]
+    [ludus.prelude :as prelude]
     [ludus.show :as show]))
 
+(def sessions (atom {}))
+
+(def current-session (atom nil))
+
+(def prompt "=> ")
+
+(defn- new-session [name] 
+  (let [session (atom {
+                       :name name 
+                       :ctx (volatile! (merge prelude/prelude {::repl true})) 
+                       :history []})]
+    (swap! sessions #(assoc % name session))
+    session))
+
+(defn repl-loop [session-atom]
+  (let [session @session-atom]
+    (print (str (:name session) prompt))
+    (flush)
+    (let [input (read-line)
+          parsed (-> input (scanner/scan) (parser/parse))
+          {result :result ctx :ctx} (interpreter/interpret-repl parsed (:ctx session))]
+      (if (= result ::interpreter/error)
+        (repl-loop session-atom)
+        (do
+          (println (show/show result))
+          (swap! session-atom #(assoc % :ctx ctx))
+          (repl-loop session-atom))))))
+
 (defn launch []
   (println "Welcome to Ludus (v. 0.1.0-alpha)")
-	(println "ludus=>")
-	(System/exit 0))
+  (let [session (new-session "ludus")]
+    (reset! current-session session)
+    (repl-loop session)))
+