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    <p>Two things:</p> <ol> <li><p>In Conal Elliott's original vision, behaviors are <em>continuous</em> in time, so they don't come with a function <code>changes</code> that indicates when they change.</p> <p>The behavior that returns the current clock time would be the prime example of a continuous behavior. It doesn't support a <code>changes</code> function, unless you specify a time step ("it generates a 'change' event every nanosecond"). But the point of "continuous" is the lack of a time step.</p> <p>In my view, this means that behaviors in Conal's sense don't support incremental updates at all. In my <a href="http://haskell.org/haskellwiki/Reactive-banana" rel="nofollow">reactive-banana</a> library, I have introduced a new data type <code>Discrete</code> that is some kind of hybrid between behaviors and events. See the documentation of the module <a href="http://hackage.haskell.org/packages/archive/reactive-banana/0.4.2.0/doc/html/Reactive-Banana-Incremental.html" rel="nofollow">Reactive.Banana.Incremental</a> for more details on the rationale.</p></li> <li><p>You are probably annoyed by having wrap each and every GUI function like <code>setBackground</code> to make it work with behaviors instead of plain values. This is were higher-order functions really shine: the wrapper is always the same, you can express it as a higher order function; here a Haskell version:</p> <pre><code>set' :: Property a -&gt; Behavior a -&gt; IO () set' property behavior = do set property (now behavior) each (\a -&gt; set property a) (changes behavior) each f event = reactimate (fmap f event) -- helper definition example = set' background red </code></pre> <p>Of course, this relies a lot on Haskell's syntax and may not be as pleasant in Scala, where some functions are written before their first argument.</p></li> </ol>
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    1. POHow should FRP work at the top level?
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    1. COI had though about a `set` like function and yes it isn't quite as nice in Scala (mainly due to the fact the `background` property and others are generally not available from outside the class). However it looks like its the best way to do it. Also, just to confirm that the Behaviours in my implementation are actually continuous. The `changes` function returns an EventSource that listens for changes to the Behaviour (its more of a utility than anything). What is the `reactimate` function here out of interest (and is `changes` referring to my `changes`)?
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    2. CO@Oetzi: Well, the behavior that returns the current clock time would be the prime example of a continuous behavior. You can't really write a `changes` function for it, because it changes "all the time".
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    3. CO@Oetzi: The `reactimate` function is part your `.each` function; the latter decomposes into an `fmap` and a `reactimate` part. The `changes` functions are supposed to be the same.
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