flatten added

stdlib/stdlib.lsp

@@ -100,6 +100,20 @@
         rslt
     ))
 
+(defun flatten(lst)
+    (do 
+        (define rslt '())
+        (for e lst
+            (if (= (type e) "list")
+                (do 
+                    (for ee (flatten e)
+                        (define rslt (push rslt ee))))
+                (define rslt (push rslt e))
+            ))
+
+        rslt
+    ))
+    
 (defun quick-sort-by (l cmp)
     (if (<= (len l) 1)
         l