[Haskell-cafe] Inputs to classic FRP: unsafeInterleaveIO/unsafePerformIO

[Ryan Ingram]

On Tue, Apr 26, 2011 at 11:44 PM, Heinrich Apfelmus <
apfelmus at quantentunnel.de> wrote:

> However, even in a demand-driven implementation, there is one optimization
> that I would like make: when there are multiple external events, say e1 and
> e2, the network splits into subnetworks that react only to one of the
> inputs. For instance, your example would split into two graphs
>
>  e1               e2
>  |  \             |  \
>  e3  e4     and   e3  e4
>  |   |            |   |
>  e5  e5           e5  e5
>
> that are independent of each other. Unlike successful filters, these
> subnetworks are known *statically* and it's worth splitting them out.
>

Yeah, I realize that as well, although you can get the same problem with a
single source, it just makes the network a bit more complicated:

e0 = source
e1 = fromLeft <$> filter isLeft e1
e2 = fromRight <$> filter isRight e1
-- rest of network the same

Anyways, the problem I was getting at is that lets say that e1 and e2 are
both Event Bool, and e1 has a True event at the same time that e2 has a
False event.

Then a behavior derived from e3 is False for that time (assuming behaviors
take the 'last' event in the list?), and a behavior from e4 is True for that
time.

  -- ryan
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