backing the entire zio stm and tref apis, on lmdb

[sidnt]

should be possible. such that whenever the app launches, it has an lmdb store to command in, and whenever it exits, it saves its state into the store. even if it crashes, the state is stored in lmdb, given lmdb's crash proof design.

• creating a TRef via TRef.make ≈ creating something in lmdb. what if the name of this TRef could also serve as the key for the corresponding lmdb item? egval students: TRef[Seq[Student]] = ... creates an actual key called 'students' in lmdb and stores the corresponding value there?

[sidnt]

how to make this ↓ run on lmdb?

def transfer(receiver: TRef[Int], sender: TRef[Int], much: Int): UIO[Int] =

  STM.atomically {
    for {
      balance <- sender.get
      _       <- STM.check(balance >= much) /*ie dereferencing a non TRef, isn't a problem*/
      _       <- receiver.update(_ + much) /*but each of these for generators, ie, <- */
      _       <- sender.update(_ - much) /*have RT as STM*/
      newAmnt <- receiver.get
    } yield newAmnt
  }

  val action: UIO[Int] =
    for {
      t <- STM.atomically(TRef.make(0).zip(TRef.make(20000)))
      (receiver, sender) = t
      balance <- transfer(receiver, sender, 1000)
    } yield balance