special handling of CDATA string

txexpr/base.rkt

@@ -352,16 +352,21 @@
       (cdata #f #f x)
       x))
 
+;; but treat CDATA strings correctly anyhow, because that's friendly
+(define (cdata-string? x)
+  (and (string? x) (regexp-match #rx"^<!\\[CDATA\\[.*\\]\\]>$" x) #t))
 
 (define+provide+safe (xexpr->html x)
   (xexpr? . -> . string?)
   (xexpr->string
    (let loop ([x x])
-     (if (txexpr? x)
+     (cond
+       [(txexpr? x)
         (let*-values ([(tag attrs elements) (txexpr->values x)]
                       [(proc) (if (memq tag '(script style))
                                   ->cdata
                                   loop)])
           ;; a little faster than `txexpr` since we know the pieces are valid
-           (txexpr-unsafe tag attrs (map proc elements)))
+          (txexpr-unsafe tag attrs (map proc elements)))]
-         x))))
+       [(cdata-string? x) (->cdata x)]
+       [else x]))))

txexpr/tests.rkt

@@ -220,4 +220,7 @@
  (check-false (findf-txexpr split-this-tx false-pred))
  
  (check-equal? (xexpr->html '(root (script "3 > 2") "Why is 3 > 2?"))
-               "<root><script>3 > 2</script>Why is 3 &gt; 2?</root>"))
+               "<root><script>3 > 2</script>Why is 3 &gt; 2?</root>")
+
+ (check-equal? (xexpr->html '(root (div "<![CDATA[3 > 2]]>") "Why is 3 > 2?"))
+               "<root><div><![CDATA[3 > 2]]></div>Why is 3 &gt; 2?</root>"))