fix a problem in WXME decoding

Thanks to Robby for the test case and for narrowing down the problem.

gui-lib/mred/private/wxme/stream.rkt

@@ -381,6 +381,15 @@
                                 (unless recur? (inc-item-count))
                                 (let ([s (with-handlers ([exn:fail:read? (lambda (x) #f)]) 
                                            (read si))])
+                                  (when (and recur? s)
+                                    ;; It's ok to have extra whitespace when reading a byte
+                                    ;; string in a sequence
+                                    (let loop ()
+                                      (define c (peek-byte si))
+                                      (unless (eof-object? c)
+                                        (when (char-whitespace? (integer->char c))
+                                          (read-byte si)
+                                          (loop)))))
                                   (if (or (not s)
                                           (not (eof-object? (read-byte si))))
                                       (fail)

gui-test/tests/gracket/wxme.rkt

@@ -927,6 +927,18 @@
         #"")
 (expect (send fi2 ok?) #f)
 
+(let ()
+  (define (wash-it b)
+    (define out-base (new editor-stream-out-bytes-base%))
+    (define out-stream (make-object editor-stream-out% out-base))
+    (send out-stream put (bytes-length b) b)
+    (define bstr (send out-base get-bytes))
+    (define in-base (make-object editor-stream-in-bytes-base% bstr))
+    (define in-stream (make-object editor-stream-in% in-base))
+    (send in-stream get-unterminated-bytes))
+  (define ex-b #"object ...  ;;\351\232\234\347\242\215\347\211\251\345\210\227\350\241\250")
+  (expect (wash-it ex-b) ex-b))
+
 ;; ----------------------------------------
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