On Nov 30, 2007 7:26 PM, Dan Weston
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