On Nov 30, 2007 7:26 PM, Dan Weston <[EMAIL PROTECTED]> wrote:
> There seems to be three salient benefits of using arrows, as I read the
> Abstract and Introduction of Benjamin Lerner, "Arrow Laws and Efficiency
> in Yampa", 2003,
> http://zoo.cs.yale.edu/classes/cs490/03-04a/benjamin.lerner/
>
> 1) The discipline of using arrows assists in avoiding space-leaks
> "The reasons underlying this...primarily stemmed from the
> availability of signals as first-class values."
> [the "ugly pain" you experience up front saves you
> chronic pain later. Self-discipline is the key to a happy life.]
I experienced the chronic pain in my initial comonadic implementation
of FRP. It was
pretty, but ran in quaadratic time :-(.
To be clear, I am not abandoning arrows in FRP. I am abandoning using
an arrow to
represent *each* object in favor of moving objects into the value level rather
than the signal level.
i.e. the following dies:
ball :: Position -> Velocity -> SF PhysIn PhysOut
...
In favor of
game = proc () -> do
rec world <- integrate initWorld -< trajectory world
...
I have an idea for an external solution though that I'm going to play
with now. I'll
report on how it goes :-)
Luke
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