_seps: ""
1 header = [{"<name>" .._seps!:"name"} .w? .$:"entity_id"]
2 vec3 = [.$_:"x" .w? .$_:"y" .w? .$_:"z"]
3 position = ["position" .w? vec3 .w?]
4 aabb = ["aabb" .w?
    "min" .w? vec3:"min" .w?
    "max" .w? vec3:"max" .w?
]
0 document = [
    header:"header" .w?
    .l({
        position:"position"
        aabb:"aabb"
    })
]