prevent `split-metas` from consuming #f args

pollen/private/split-metas.rkt

@@ -2,6 +2,7 @@
 (provide (all-defined-out))
 
 (define (split-metas tree meta-key)
+  (define missing-sym (gensym))
   (define matches null)
   
   (define (meta? x)  ; meta has form (define-meta key value)
@@ -10,17 +11,17 @@
   (define rest
     (let loop ([x (if (list? tree) tree (list tree))])
       (cond
-        [(meta? x) (set! matches (cons x matches)) #f]
-        [(list? x) (filter (λ(x) x) (map loop x))]
+        [(meta? x) (set! matches (cons x matches)) missing-sym]
+        [(list? x) (filter (λ(x) (not (eq? x missing-sym))) (map loop x))]
         [else x])))
   
   (values (apply hasheq (apply append (reverse (map cdr matches)))) rest))
 
 (module+ test
   (require rackunit)
-  (let-values ([(metas rest) (split-metas '(root (div (define-meta foo "bar") "hi") "zim" (define-meta foo "boing") "zam") 'define-meta)])
+  (let-values ([(metas rest) (split-metas '(root (div #:kw #f (define-meta foo "bar") "hi") "zim" (define-meta foo "boing") "zam") 'define-meta)])
     (check-equal? metas '#hasheq((foo . "boing")))
-    (check-equal? rest '(root (div "hi") "zim" "zam")))
+    (check-equal? rest '(root (div #:kw #f "hi") "zim" "zam")))
   (let-values ([(metas rest) (split-metas '(root (define-meta dog "Roxy") (define-meta dog "Lex")) 'define-meta)])
     (check-equal? metas '#hasheq((dog . "Lex"))))
   (let-values ([(metas rest) (split-metas '(root (define-meta dog "Roxy") (div (define-meta dog "Lex"))) 'define-meta)])

pollen/private/ts.rktd

@@ -1 +1 @@
-1455046915
+1455065350