-- memoization of `forkAt` seems really useful, lets you incrementally recompute batch jobs
-- it would be cool if you could memoize to either ephemeral or durable storage
-- you could have memoization be a global decision made by the handler, but this is not enough control - you don't want to memoize everything
-- also want to be able to race computations and whichever finished first you use its result

ability Remote t g where
  -- forkAt : Location -> '{g} a -> () -- no 
  forkAt : Location -> '{g} a -> t a 
  fail : Failure -> x
  here : Location

  -- could split this up into r/w x ephemeral/durable
  -- await/ephemeral could be in read-only
  -- put could be in write
  ephemeral : Location -> id a -> t a
  durable : Location -> id a -> t a
  lexical : Location -> id a -> t a
  finished : t a -> Boolean
  await : t a -> a
  put : a -> t a -> () 

forkAt alice 'let
  ..
  put

---

  -- where Mode
  forkAt : Location -> '{g} a -> t a
  -- issue with this is you want to check the cache before
  -- launching the task!
  cache : Mode -> t a -> t
  
  -- IVar Ephemeral a
  ephemeral : Location -> id a -> IVar Ephemeral a
  -- IVar Durable a
  durable : Location -> id a -> IVar Durable a
  finished : IVar s a -> Boolean
  await : IVar a -> s a
  put : a -> IVar a -> () 

'{Remote t {IVars}} Nat

memoAt : Location -> '{g} a ->{Remote t g} (IVar a)
memoAt loc c = 
  ivar = IVars.new c
  if finished ivar then 
    await ivar
  else
    forkAt loc 'let
      t = forkAt loc c  
      a = await t
      IVars.put a ivar
    ivar

-- 
-- {Remote t {IVars}} x
ability IVars where
  -- IVar Ephemeral a
  ephemeral : Location -> id a -> IVar Ephemeral a
  -- IVar Durable a
  durable : Location -> id a -> IVar Durable a
  finished : IVar s a -> Boolean
  await : IVar a -> s a
  put : a -> IVar a -> () 

ability IVars.R where
  -- IVar Ephemeral a
  -- ephemeral : Location -> id a -> IVar Ephemeral a
  -- IVar Durable a
  -- durable : Location -> id a -> IVar Durable a
  finished : IVar s a -> Boolean
  await : IVar a -> s a
  -- put : a -> IVar a -> () 

ability IVars.Durable.W where
  -- IVar Ephemeral a
  ephemeral : Location -> id a -> IVar Ephemeral a
  -- IVar Durable a
  durable : Location -> id a -> IVar Durable a
  put : a -> IVar a -> () 

  -- ask for the hash that was used to compute it
  -- cancel :  


---

ability IVar where
   
ask the IVar for the hash of what was used to compute it
areWeThereYetMom - to tell us if it’s still being computed
read: IVar a -> Optional a
if this has already been computed, give me a reference to where this data has been put

ask the IVar for the hash of what was used to compute it
areWeThereYetMom - to tell us if it’s still being computed
read: IVar a -> Optional a
if this has already been computed, give me a reference to where this data has been put