function const_data({ type, value }) {
  switch (type) {
    case "decimal":
    case "integer":
      return { type: "number", value };
    case "string":
      return { type: "string", value: value.slice(1, -1) };
  }

  switch (value) {
    case "true":
    case "false":
      return { type: "boolean", value: value === "true" };
    case "Infinity":
    case "-Infinity":
      return { type: "Infinity", negative: value.startsWith("-") };
    case "[":
      return { type: "sequence", value: [] };
    case "{":
      return { type: "dictionary" };
    default:
      return { type: value };
  }
}
@param {object} token
@param {string} token.type
@param {string} token.value