Static values language extension proposal

[Tim Watson]

On 24 Jan 2014, at 17:59, Carter Schonwald wrote:
> 0) I think you could actually implement this proposal as a userland library, at least as you've described it. Have you tried doing so? 
> 

I didn't pick up on that at all - how would we be able to do that?

> 1) what does this accomplish that can not be accomplished by having various nodes agree on a DSL, and sending ASTs to each other?
>      1a) in fact, I'd argue (and some others agree, and i'll admit my opinions have been shaped by those more expert than me) that the sending a wee AST you can interpret on the other side is much SAFER than "sending a function symbol thats hard coded hopefully into both programs in a way that it means the same thing".  I've had many educational conversations with 
> 

I've still not seen a convincing example of how to do this though. It would help if someone explained what this would look like, running over two (or more) separate binaries and still shipping code. It's just that, afaict, that AST wouldn't be so "wee" once it had to represent any arbitrary expression. One could, of course, just ship source (or some intermediate representation), but that would also require compiler infrastructure to be installed on the target.

> 2) how does it provide more type safety than the current TH based approach? (I've seen Tim and others hit very very gnarly bugs in cloud haskell based upon the "magic static values" approach). 
> 

This is definitely true, but I see it as a problem related to our use of TH rather than our current use of closures and 'Static' per se. Having said that, it can be toe-curlingly difficult to work with closure/static sometimes, so *anything* that makes this easier sounds good to me.

> 
> to repeat: have you considered defining an AST type + interpreter for the computations you want to send around, and doing that? I think its a much simpler, safer, easier, flexible and PORTABLE approach, though one current CH doesn't do (though the folks working on CH seem to be receptive to switching to such a strategy if someone validates it)
> 

I/we are, I think, amenable to doing whatever makes the most sense. This could include doing more than one thing, when it comes to dealing with 'statics'. Personally I think the proposal sounds interesting, though as I mentioned in my previously mail, I haven't had time to sit down and look at it in detail yet.

Cheers,
Tim