Clearing buffer for web worker REPL on error

Fixes #318

src/read.lisp

@@ -547,10 +547,14 @@
           (skip-whitespaces-and-comments stream)
           (let ((ch (%peek-char stream)))
             (cond
-              ((or (null ch) (char= ch #\)))
+              ((null ch)
                (if eof-error-p
                    (error "End of file")
                    eof-value))
+              ((char= ch #\))
+               (if eof-error-p
+                   (error "unmatched close parenthesis")
+                   eof-value))
               ((char= ch #\()
                (%read-char stream)
                (%read-list stream eof-error-p eof-value))

src/worker.lisp

@@ -47,12 +47,14 @@
                 (print result)))
           (error (err)
             (let ((*web-worker-output-class* "jqconsole-error"))
+              (clear-buffer)
               (format t "ERROR: ")
               (apply #'format t (!condition-args err))
               (terpri)))))
       (catch (err)
         (let (((*web-worker-output-class* "jqconsole-error"))
               (message (or (oget err "message") err)))
+          (clear-buffer)
           (format t "ERROR[!]: ~a~%" message))))))
 
 
@@ -88,6 +90,9 @@
     (setf *stdin-buffer* (concat *stdin-buffer* input))
     *stdin-buffer*))
 
+(defun clear-buffer ()
+  (setf *stdin-buffer* ""))
+
 (defun %peek-char-stdin (&rest args)
   (if (< 0 (length *stdin-buffer*))
       (char *stdin-buffer* 0)