On Jan 25, 2011, at 12:45 PM, Michael Snoyman wrote:

On Tue, Jan 25, 2011 at 8:35 PM, Jeremy Shaw <jeremy@n-heptane.com> wrote:

On Jan 25, 2011, at 12:10 PM, Michael Snoyman wrote:

7. the ServerPartT monad has a built-in FilterT monad which makes it
easy
to apply a function (Response -> Response) to modify the response.

In all honesty, this is an argument *against* frameworks, not for
them: at a WAI level, we don't need a FilterT monad, since an
application is just a function.

Yes, precisely. As I see it, the difference between the two approaches would be:

* Yesod's is a little bit faster. And I mean a *little* bit.
* Happstack's is more powerful, in that you can do more than simply
append a header.

Would you concur?

Yes. The question, though isn't whether the Happstack vs Yesod approach is better, but whether having that functionality in some form at all is better than the bare bones WAI which gives you nothing :p Since both frameworks implement such functionality, clearly we must think the answer is 'yes' ;)