sourcekitten structure --text "struct A { func b() {} }"

structure.json

{
  "key.length": 24,
  "key.diagnostic_stage": "source.diagnostic.stage.swift.parse",
  "key.substructure": [
    {
      "key.bodylength": 13,
      "key.namelength": 1,
      "key.length": 24,
      "key.kind": "source.lang.swift.decl.struct",
      "key.name": "A",
      "key.accessibility": "source.lang.swift.accessibility.internal",
      "key.nameoffset": 7,
      "key.bodyoffset": 10,
      "key.substructure": [
        {
          "key.bodylength": 0,
          "key.namelength": 3,
          "key.length": 11,
          "key.kind": "source.lang.swift.decl.function.method.instance",
          "key.name": "b()",
          "key.accessibility": "source.lang.swift.accessibility.internal",
          "key.nameoffset": 16,
          "key.bodyoffset": 21,
          "key.offset": 11
        }
      ],
      "key.offset": 0
    }
  ],
  "key.offset": 0
}