Fall back to general fontification of source blocks if lang attr is n…

…ot given

adoc-mode.el

@@ -2109,9 +2109,10 @@ Group 2 contains the block delimiter.")
  "Search for next adoc-code block up to LAST.
 NOERROR is the same as for `search-forward'.
 
-Return the source block language and
+Return a string with the source block language and
 set match data if a source block is found.
-Otherwise return nil.
+If the source block is given without the language attribute return t.
+If no source block is found return nil.
 
 The overall match data begins at the
 header of the code block and ends at the end of the
@@ -2167,9 +2168,11 @@ Use this function as matching function MATCHER in `font-lock-keywords'."
  (end-src (match-end 1))
  (end-src+nl (if (eq (char-after end-src) ?\n) (1+ end-src) end-src))
  (size (1+ (- end-src start-src))))
- (if (if (numberp adoc-fontify-code-blocks-natively)
- (<= size adoc-fontify-code-blocks-natively)
- adoc-fontify-code-blocks-natively)
+ (if (and
+ (if (numberp adoc-fontify-code-blocks-natively)
+ (<= size adoc-fontify-code-blocks-natively)
+ adoc-fontify-code-blocks-natively)
+ (stringp lang))
  (adoc-fontify-code-block-natively lang start-block end-block start-src end-src)
  (add-text-properties
  start-src