Art interface: cell and thunk are incomplete / broken

[matthewhammer]

The Nominal Adapton interface is broken for functions cell and thunk. This is my fault. Kyle has been aware of this for a while, but we haven’t prioritized fixing it. Now, it’s biting Nick.

The problem is that both functions take a name, and then ignore it, rather than use it to memorize the art that they return, as they should do.

In the meantime, here’s a workaround that I used for AVL trees:
https://github.com/plum-umd/adapton.ocaml/blob/master/Source/adapton_structures/SpreadTree.ml#L1430

In particular, the function nm_tree creates a memo table that memoizes tree structures based on a name. It does something close to what cell should do.

Nick, I think you can adapt this code to get memo tables that are keyed on names. In particular, something like this:

  let mfn = MyArt.mk_mfn (Name.gensym "my_table") 
      (module MyData) 
      (fun r data -> data)
  in 
  fun nm data -> (mfn.MyArt.mfn_nart nm data)

That should give you a memo table where the same name yields the same thunk (physically).