Best way to replace a transcoder?

[rossabaker]

I'm trying to extend the org-hugo-src-block encoder with additional functionality. One way to do this is to define a derived backend:

(org-export-define-derived-backend 'rab-hugo 'hugo
  :translate-alist '((src-block . rab/ox-hugo-src-block)))

The problem is the export commands. There's a substantial amount of logic in org-hugo-export-wim-to-md and its related helpers. The 'hugo backend is hardcoded into a handful of calls to org-export functions throughout ox-hugo.el. To use my simple transcoder in a derived backend, it seems like I'd be copying hundreds of lines of export code.

My interim solution is something more destructive:

(map-put! (org-export-backend-transcoders
                         (org-export-get-backend 'hugo))
                        key value)

I only have one ox-hugo site, so mutating that map doesn't hurt in practice, but it feels wrong. I'd be in trouble if I also had a "vanilla" ox-hugo site. Is there a better way to extend a transcoder or two?