scopeToCSSClass = (name, { prefix }) => {
    // sub-language
    if (name.startsWith("language:")) {
      return name.replace("language:", "language-");
    }
    // tiered scope: comment.line
    if (name.includes(".")) {
      const pieces = name.split(".");
      return [
        `${prefix}${pieces.shift()}`,
        ...(pieces.map((x, i) => `${x}${"_".repeat(i + 1)}`))
      ].join(" ");
    }
    // simple scope
    return `${prefix}${name}`;
  }
@param {string} name
@param {{prefix:string}} options