> erlyweb uses a component system for rendering pages. It makes most of
> my controller functions return lists like this:

>    [{data,post:title(Post)},
>     {ewc,post,contents,[A,Post]},
>     {ewc,comment,comments,[A,post:comments(Post)]}]

> The view function then looks like:

>    <%@ show([Title,Contents,Comments]) %>
>      <h1><% Title %></h1>
>      <div class="post_contents"><% Contents %></div>
>      <ul class="comments><% Comments %></ul>

> I really like this, because it allows me to separate the view-logic
> for things like contents and comments out from each other, which
> makes changing the behaviour of these quite simple, localised, and re-
> useable. (In fact, as I re-write portions of erlyweb for my purposes,
> the component system is something that I haven't touched at all
> because it works quite well.) However, it has an inherent limitation:
> none of those functions can return data to be rendered outside of
> their components. In my case, I'd like to be able to set <title>
> tags, which means that the top-level controller function (by top-
> level, I mean the one referenced in the URL; like in /post/show/12,
> the top-level controller function would be show/2) needs to somehow
> return information to be rendered outside its little sandbox.

> I see that Vimagi doesn't set <title> tags (neither <http://
> vimagi.com/p/0PXmMRe6hGV> nor <http://vimagi.com/users/feeling3_4>
> set one, at least, and those are where I'd expect to see them), but
> BeerRiot does (<http://beerriot.com/beer/view/1751>; BTW I do love
> the idea of having a controller called "beer_controller").

> It isn't limited to <title>s (for instance, I may want to alert the
> browser that an RSS equivalent of this page exists, or what the
> caching TTL is for this page in the HTTP headers). Conceptually, how
> would one go about returning this extra information, while still
> using the component system (I now have a lot of code that uses it
> that I'd like to not re-write :) )?