Add history and ok/err functionality to REPL.

src/examples/repl.pbl

@@ -1,20 +1,34 @@
 #!/usr/bin/pl
+(def _history ())
+(def __history (fn (_h) (
+  (prnl (at 0 _h))
+  (if (> (len _h) 0) (
+    (__history (rest _h))
+  ) ())
+)))
+
+(def history (fn () (__history _history)))
+
 (def repl (fn () (
   (prn "pebblisp::> ")
+
   (def input (inp))
+
   (if (= input "q") () (
+      (def _history (ap _history input))
       ;(switch input (
-      ;  ("clear" (fn () (sys "clear")))
+      ;  ("clear" (sys "clear"))
       ;))
 
       (if (= input "") () (
         (if (= input "clear") (sys "clear") (
           (def ret (eval input))
-        (if (iserr ret) (prn "X  =>  ") (prn "Ok =>  "))
+          (if (iserr ret)
+            (prn "X  =>  ")
+            (prn "Ok =>  "))
           (prnl ret)
-        (prn "")))))
-      (repl)
-  ))
-)))
+          (prnl ""))))
+      )
+      (repl))))))
 
 (repl)