;; content-on-sx — global find/replace across text-bearing blocks.
;;
;; Replaces every occurrence of `from` with `to` in the text field of text /
;; heading / code / quote blocks, tree-wide (via the transform layer). For
;; renaming a term throughout a document. Immutable; case-sensitive.
;;
;; Requires (loaded by harness): block.sx, transform.sx (content/map-blocks).

(define
  fr-in?
  (fn
    (x xs)
    (cond
      ((= (len xs) 0) false)
      ((= (first xs) x) true)
      (else (fr-in? x (rest xs))))))

(define
  fr-has-text?
  (fn (b) (fr-in? (blk-type b) (list "text" "heading" "code" "quote"))))

(define
  content/find-replace
  (fn
    (doc from to)
    (content/map-blocks
      doc
      fr-has-text?
      (fn
        (b)
        (blk-set b "text" (replace (str (blk-get b "text")) from to))))))