How to index json?

[Luk-ESC]

(defwindow top-bar
           :monitor 0
           :geometry (geometry :x "0%"
                               :y "0%"
                               :width "100%"
                               :height "30px"
                               :anchor "top center")

           :exclusive true
           :reserve (struts :distance "0px" :side "top")
           :windowtype "dock"
           :wm-ignore false
           (box :orientation "horizontal"
		:halign "center"

	    EWW_BATTERY["BAT0"]
	
))

That errors with

error: Wrong type of expression
   ┌─ /home/eschb/.config/eww/eww.yuck:21:17
   │
21 │         EWW_BATTERY["BAT0"]
   │                    ──────── Expected a `List` here
   │
   → Expected: List
          Got: Array

which I don't understand at all.
Sorry if I'm being stupid but looking at https://elkowar.github.io/eww/expression_language.html I thought this should work.

[w-lfchen]

The expression has to be placed inside {...}, so simply surround EWW_BATTERY["BAT0"] with curly braces and it should work.

[Luk-ESC]

Thank you!