Am Freitag, 10. April 2009 18:41 schrieb Patai Gergely: > is based on some unsafePerformIO dark magic (that might easily break > depending on many factors)
I wonder if this breaks referential transparency. Say, you define a signal s and use s twice in some expression. s may be evaluated once and it maybe evaluated twice. Does this make a difference? In the Haddock docs, you say that repeated evaluation of the same value is prevented by caching. However, caching probably only works if the signal in question is only evaluated once. If it’s evaluated twice, the second “instance” probably cannot reuse cached values of the first “instance”. Is it possible that thereby the second “instance” has different values than the first one? A well known FRP problem is that the values of a signal with internal state (an accumulating signal) depend on the time when the signal is started, i.e., when accumulation starts. When are your signals started? At evaluation time? If yes, doesn’t this mean that the meaning of a signal depends on evaluation time so that evaluating the same signal expression twice actually results in two different signals? Best wishes, Wolfgang _______________________________________________ Haskell-Cafe mailing list [email protected] http://www.haskell.org/mailman/listinfo/haskell-cafe
