From 18bcf6d8c6e2b016d17e25870859f3a30cc4dea3 Mon Sep 17 00:00:00 2001
From: Scott Richmond <kredati@users.noreply.github.com>
Date: Fri, 27 May 2022 20:02:32 -0400
Subject: [PATCH] More minor repl improvements

---
 src/ludus/repl.clj | 123 ++++++++++++++++++++++++++-------------------
 1 file changed, 72 insertions(+), 51 deletions(-)

diff --git a/src/ludus/repl.clj b/src/ludus/repl.clj
index 406449c..da4de64 100644
--- a/src/ludus/repl.clj
+++ b/src/ludus/repl.clj
@@ -1,11 +1,11 @@
 (ns ludus.repl
   (:require
-   [ludus.scanner :as scanner]
-   [ludus.parser :as parser]
-   [ludus.interpreter :as interpreter]
-   [ludus.prelude :as prelude]
-   [ludus.show :as show]
-   [ludus.data :as data]))
+    [ludus.scanner :as scanner]
+    [ludus.parser :as parser]
+    [ludus.interpreter :as interpreter]
+    [ludus.prelude :as prelude]
+    [ludus.show :as show]
+    [ludus.data :as data]))
 
 (declare repl-prelude new-session)
 
@@ -15,40 +15,59 @@
 
 (def prompt "=> ")
 
+(defn- exit []
+  (println "\nGoodbye!")
+  (System/exit 0))
+
 (def base-ctx (merge prelude/prelude
-                     {::repl true
-                      "repl"
-                      {::data/struct true
-                       ::data/type ::data/ns
-                       ::data/name "repl"
+                {::repl true
+                 "repl"
+                 {::data/struct true
+                  ::data/type ::data/ns
+                  ::data/name "repl"
 
-                       :flush
-                       {:name "flush"
-                        ::data/type ::data/clj
-                        :body (fn []
-                                (let [session @current-session]
-                                  (swap! session #(assoc % :ctx (volatile! base-ctx)))
-                                  :ok))}
+                  :flush
+                  {:name "flush"
+                   ::data/type ::data/clj
+                   :body (fn 
+                           ([]
+                            (let [session @current-session]
+                              (swap! session #(assoc % :ctx (volatile! base-ctx)))
+                              :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"
-                        ::data/type ::data/clj
-                        :body (fn [name]
-                                (let [session (new-session name)]
-                                  (reset! current-session session)
-                                  :ok))}
+                  :new
+                  {:name "new"
+                   ::data/type ::data/clj
+                   :body (fn [name]
+                           (let [session (new-session name)]
+                             (reset! current-session session)
+                             :ok))}
 
-                       :switch
-                       {:name "switch"
-                        ::data/type ::data/clj
-                        :body (fn [name]
-                                (if-let [session (get @sessions name)]
-                                  (do
-                                    (reset! current-session session)
-                                    :ok)
-                                  (do
-                                    (println "No session named" name)
-                                    :error)))}}}))
+                  :switch
+                  {:name "switch"
+                   ::data/type ::data/clj
+                   :body (fn [name]
+                           (if-let [session (get @sessions name)]
+                             (do
+                               (reset! current-session session)
+                               :ok)
+                             (do
+                               (println "No session named" name)
+                               :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)
-          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)
-        (do
-          (println (show/show result))
-          (when (not (= @ctx @orig-ctx))
-            (swap! session-atom #(assoc % :ctx ctx)))
-          (repl-loop))))))
+    (let [raw-input (read-line)]
+      (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)
+            (recur)
+            (do
+              (println (show/show result))
+              (when (not (= @ctx @orig-ctx))
+                (swap! session-atom #(assoc % :ctx ctx)))
+              (recur))))))))
 
 (defn launch []
   (println "Welcome to Ludus (v. 0.1.0-alpha)")