src/language-css/parser-postcss.js/parseWithParser
function parseWithParser(parse, text, options) {
  const parsed = parseFrontMatter(text);
  const { frontMatter } = parsed;
  text = parsed.content;

  let result;

  try {
    result = parse(text);
  } catch (error) {
    const { name, reason, line, column } = error;
    /* istanbul ignore next */
    if (typeof line !== "number") {
      throw error;
    }
    throw createError(`${name}: ${reason}`, { start: { line, column } });
  }

  result = parseNestedCSS(addTypePrefix(result, "css-"), options);

  calculateLoc(result, text);

  if (frontMatter) {
    frontMatter.source = {
      startOffset: 0,
      endOffset: frontMatter.raw.length,
    };
    result.nodes.unshift(frontMatter);
  }

  return result;
}