better split-meta-elements error

9 years ago · 2dae1ca31f
parent 97b4dea0ca
commit 2dae1ca31f
1 changed files with 2 additions and 0 deletions
--- a/metas.rkt
+++ b/metas.rkt
@ -31,6 +31,8 @@
      [else (reverse acc)])))

 (define (split-meta-elements x) ; pull metas out of doc and put them into meta-elements accumulator
+  (when (not (txexpr? x))
+    (error 'split-meta-elements "Not a txexpr: ~v" x))
  (define-values (thing-without-meta-elements meta-elements) (splitf-txexpr x meta-element?))
  ;; trivial metas are discarded
  (define exploded-meta-elements (append-map explode-meta-element (filter nontrivial-meta-element? meta-elements)))