[reactive] New implementation: Reactant (99% incomplete)

[Thomas Davie]

On 30 Jul 2009, at 00:18, Svein Ove Aas wrote:

> In the interest of throwing code out early, at
> http://github.com/Baughn/Reactant/tree/master there is now the first
> draft of a different approach to Conal-style FRP.
>
> Well, I say "first draft", but the code in there currently only
> implements ITime - eg. Improving Time. Fortunately that's also the
> hardest bit; the source of most of the bugs, and the reason to use
> unamb.
>
> This implementation doesn't use unamb, though. Instead, I'm using a
> push-style approach, where the various function calls - compare, etc.
> - use semaphores to block until the ITimes they are comparing are
> sufficiently defined for them to return an answer.
>
>
> It's my hope that, although this approach is also quite bug-prone, I
> will be able to side-step the issues with unamb this way. If nothing
> else, performance should increase noticably; there is no need for this
> system to fork any threads except to deal with timeouts, thus forking
> happens considerably less often than with unamb.
>
> I'll hopefully have more for you in a few days. Until then, you may be
> entertained by looking closely at the rather eldritch code, and if
> anyone spots a potential bug, that's just a bonus.

Glad to see there's (yet more) people working on fun ideas for how to  
get this lovely API to work well.  Something I'd suggest though –  
Conal's reactive has quite a large set of tests, mostly checking that  
the implementations of the various classes respect the laws they're  
meant to, but also checking a few other things.  It'd be really lovely  
if you could copy/paste them over to check you're sticking to the  
semantics as it was originally envisaged (IIRC, conal's doesn't quite,  
but is very close).

Cheers

Bob