Pass variable as content in MDX ?

I want to pass a variable to rehype-pretty-code as content in MDX, something like this:

```mdx title="Demo.mdx"
{frontmatter.rawmdx}
\```

frontmatter.rawmdx is created by astro-m2dx

Is It possible?

some imagine syntax:

```mdx title="Demo.mdx" content={frontmatter.rawmdx}
\```

I don't think metastrings can contain variable content; they're just raw strings.

What we can do is allow a map of the variable content in the options:

const options = {
  contentMap: {
    test: '// comment',
  }
};

```js contentKey="test"
```

Would this work?

Best option now is just to use a component to pass runtime values (server or client): https://rehype-pretty-code.netlify.app/#react-server-component