json arrays not working (?) - possibly syntax error?

[theNoof]

Hey, i tried to make a widget that lists multiple disk partitions & there percentage used. my approach:

(defwidget partition-usage [partitions] 
  (box
    :orientation "vertical"
    (for partition in partitions
      (label :text {EWW_DISK[partition].used_perc}))))

but it just doesnt wanna work

also, partitions is a json array. should i use something else?
it also doesnt show when i leave out the part with EWW_DISK and just use partition.
am i using the for loop wrong? or maybe something else? idk please help