:setup-children for nested groups?

[mekeor]

This nested, matrix-like, two-dimensional transient works fine:

(defun example () (interactive) (message "example"))

(transient-define-prefix example-static ()
  [ [ "Left column"
      ("d" "d" example :transient t)
      ("f" "f" example :transient t)]
    [ "Right column"
      ("j" "j" example :transient t)
      ("k" "k" example :transient t)]])

But I want to determine the groups dynamically, when the transient is called. I tried this:

(transient-define-prefix example-dynamic ()
  [ :setup-children
    (lambda (_)
      (transient-parse-suffixes
       'not-sure-about-this
       [ :class transient-row
         [ "Left column"
           ("d" "d" example :transient t)
           ("f" "f" example :transient t)]
         [ "Right column"
           ("j" "j" example :transient t)
           ("k" "k" example :transient t)]]))])

But it calling this transient results in this error:

transient-setup: Lisp nesting exceeds `max-lisp-eval-depth': 1601

I also tried other variations. For example, when I remove :class transient-row, I get this error:

transient-setup: No applicable method: transient-format, #s(transient-column 1 nil nil nil nil nil nil nil nil ...)

What am I doing wrong? How can I dynamically build a two-dimensional transient?

[tarsius]

(transient-define-prefix example-dynamic ()
  [:class transient-columns
   :setup-children
   (lambda (_)
     (transient-parse-suffixes
      'example-dynamic
      '(["Left column"
         ("d" "d" transient-echo-arguments :transient t)
         ("f" "f" transient-echo-arguments :transient t)]
        ["Right column"
         ("j" "j" transient-echo-arguments :transient t)
         ("k" "k" transient-echo-arguments :transient t)])))])

This nested, matrix-like, two-dimensional transient

Such layouts have to use the transient-columns group type, there is no other group type that supports more than one dimension.

When using :setup-children the class has to be specified but you picked the wrong class and specified it in the wrong place.

Using [["Left column" ... would actually work, but using '(["Left column" ... is better because it discourages the mentioned mistakes.

I'll have to think about how to make it more obvious in the manual. I might also add an example.

[tarsius]

I've added the example in cfd17a7.