add lang

defs.rkt

@@ -9,6 +9,7 @@
             (list/c 'date integer? integer? integer?)
             (list/c 'title string?)
             (list/c 'slug string?)
+            (list/c 'lang string?)
             (cons/c 'tags (listof string?))
             (list/c 'summary string?)
             (cons/c 'authors (listof string?)))))
@@ -19,4 +20,6 @@
     [(cons _ rst) rst]))
 
 (define (metadata-ref+ md key [default (λ () (error "no such key"))])
-  (first (metadata-ref md key default)))
+  (match (assoc key md)
+    [#f (if (procedure? default) (default) default)]
+    [(list _ snd) snd]))

templates/page.html.rkt

@@ -1,7 +1,7 @@
 #lang s-exp "../xtemplate.rkt"
 
 `(html
-  ([lang "en"])
+  ([lang ,(metadata-ref+ metadata 'lang "en")])
   (head
     ()
     (!HTML-COMMENT () " this page made with: trans rights 🏳️‍⚧️ ")