(use-modules (haunt reader commonmark)
             (haunt reader)
             (haunt post)
             (guix build utils)
             (srfi srfi-1))

(define files
  (find-files "posts" "\\.(md|sxml)$"))

(define authors
  (delete-duplicates
   (append-map (lambda (file)
                 (define reader
                   (if (string-suffix? ".md" file)
                       commonmark-reader
                       sxml-reader))

                 (map string-trim-both
                      (string-split (post-ref (read-post reader file) 'author)
                                    #\,)))
               files)))