[Haskell-cafe] Re: Can this be done?

[Achim Schneider]

Evan Laforge <qdunkan at gmail.com> wrote:

> On Wed, Feb 11, 2009 at 9:34 PM, Alistair Bayley
> <alistair at abayley.org> wrote:
> > 2009/2/11 Cristiano Paris <cristiano.paris at gmail.com>:
> >> I wonder whether this can be done in Haskell (see muleherd's
> >> comment):
> >>
> >> http://www.reddit.com/r/programming/comments/7wi7s/how_continuationbased_web_frameworks_work/
> >
> > WASH did/does something similar. You can certainly write
> > applications in a similar, workflow-ish style (rather than like a
> > state machine).
> 
> To hijack the subject, what happened to WASH?  The paper seemed like
> it was full of interesting ideas, but the implementation seems to have
> failed to capture many hearts.  Now it seems like a stagnant project.
> What were the fatal flaws?
> 
I got curious and made two pages point to each other, resulting in as
many stale continuations as your left mouse button would permit. While
the model certainly is cool, I'm not aware of any implementation that
even comes close to having production-safe (that is, non-abusable)
semantics.

Continuations might also be overkill: For things like server-side
checked[1] POST hurdle races, specifying a list of form/predicate/action
triples seems to be the nicer way to go. Generalising, fgl should be
able to take care of any control flow imaginable.


[1] Am I the only one who can't stand those buggy js-forms, especially
    if the client side has a different notion of valid input than the
    server?

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