It's Kinda FRP-y

kinda-ferpy is a simplified model for functional reactive programming. Signals, events, and dependency relationships are implicitly defined by monitoring program control. The implementation uses a ported and patched form of MaiaVictor’s PureState library.

(require kinda-ferpy)

(define x (stateful-cell 1))
(define y (stateful-cell 1))
(define sum (stateful-cell (+ (x) (y))))

(displayln (sum)) ; 2
(y 8)
(displayln (sum)) ; 9

For a less trivial example, here’s a progression from a Markdown file to an HTML document, plus a few ways to use it. % is an alias of stateful-cell, so I’ll shorten it here.

(require kinda-ferpy markdown)

(define md-path
  (% (build-path "index.md")))

(define html-path
  (% (path-replace-extension (md-path)
                             #".html")))

(define content-xexpr
  (% (parse-markdown (md-path))))

(define page-xexpr
  (% `(html (head (title "My Page"))
            (body ,(content-xexpr)))))

(define html-string
  (% (string-append "<!DOCTYPE html>"
                    (xexpr->html (page-xexpr)))))

(define html-link
  (% (string-append "/"
                    (path->string ,(html-path)))))

This hooks up a file system path to a Markdown file and expresses different output formats regarding an HTML document. To produce new documents, you only need to change md-path.