hi @U05CLS4TF6Z both these example work with the latest clerk

(clerk/with-viewers
 (clerk/add-viewers [{:pred number? :render-fn '(fn [_ _] [:em "num"])}])
 (clerk/table [[1] [2]]))

(clerk/table
 {::clerk/viewers (clerk/add-viewers [{:pred number? :render-fn '(fn [_ _] [:em "num"])}])}
 [[1] [2]])

thank you!

the point is with-viewers (and the associated ::clerk/viewers option) actually do specify all the available viewers, so clerk/dd-viewers prepends your custom ones to the list of the defaults

I appreciate it, I couldn’t figure out that connecting piece from the docs

So interestingly, this doesn’t work when I want the number formatter to be used within the table. Attaching a snippet

The number viewer must first be attached to a table viewer

that’s very odd, there should be no need to add the number viewer to the inner table viewers

I guess that has something to do with named viewers

in fact this works again:

(def n-viewer
  (dissoc (assoc viewer/number-viewer :render-fn '(fn [_ _] [:em "num"]))
          :name))
(clerk/table
 {::clerk/viewers (clerk/add-viewers [n-viewer])}
 [[1] [2]])

Yep, dissocing the name allowed it to work

that must be something related to how add-viewers work in wrt named viewers, but I don’t recall why we did this: https://github.com/nextjournal/clerk/blob/fc6df7186bfea2571fff2dd790d0ad63f8d6295f/src/nextjournal/clerk/viewer.cljc#L666-L670 cc @U5H74UNSF?

Either way, it’s an amazing tool and I want to thank yall for creating it!

add-viewers! now does in-place positional replacement to make it easier to override them

there’s also a first-class :add-viewers attribute on the table-viewer, also makes customization easier

see the Improve viewer customization section in https://github.com/nextjournal/clerk/blob/main/CHANGELOG.md#015957-2023-09-28

still ned to do a pass to clarify this in the docs

I saw that originally, but wasn’t sure which was the preferred/recommended way to do

> Anonymous viewers (without a :name) or new named viewers will be prepended to the viewer stack I see, but having to dissoc the name of an existing viewer to have it take precedence sounds a bit odd

(ns scratch
  (:require [nextjournal.clerk.viewer :as viewer]
            [nextjournal.clerk :as clerk]))

(def my-number-viewer
  (assoc viewer/number-viewer :render-fn '(fn [_ _] [:em "num"])))

(clerk/add-viewers! [(update viewer/table-viewer :add-viewers clerk/add-viewers [my-number-viewer])])

(clerk/table [[1] [2]])

this is the recommended way, no need to dissoc anything

but use :add-viewers instead of :nextjournal/viewers because the former takes precendence

Thanks!

let me know if that makes sense

Yep, makes sense. The add-viewers! changes the default viewers correct?

or rather, if you used :nextjournal/viewers but left the :add-viewers on the table-viewer as-is, the table viewer would still use its original number viewer, so you woudln’t see the change

yes, can also do it just locally

add-viewers! changes the defaults for that namespace

@U9EQP1K0X let’s go over this and document it next week