0. #lang racket
1. (define (extract-meta-data content)
2.   (match content
3.          [(struct h:html-full (attributes content))
4.           (apply append (map extract-pcdata content))]
5.          [(struct tag-name (attributes))
6.           (get-content-if-named attributes)]
7.          [(struct h:html-element (attributes)) null]))

=>

eval:2:0: match: h:html-full does not refer to a structure

definition

at: h:html-full

in: (struct h:html-full (attributes content))