module C = Common
module V = Value

module Mv =
  struct
    type t = C.meta
    let compare (C.Mv i1) (C.Mv i2) = Stdlib.compare i1 i2
  end

module MvMap = Map.Make(Mv)

type mentry
  = Unsolved of V.value (* type *)
  | Solved of (V.value * V.value) (* solution : type *)

let metaEntries : mentry MvMap.t ref = ref MvMap.empty

let getMetaEntry (m : C.meta) =
  MvMap.find m !metaEntries

let modMetaEntry (f : mentry MvMap.t -> mentry MvMap.t) =
  metaEntries.contents <- f !metaEntries

(* TODO: if not found then insert new meta for the type somehow *)
let getMetaType (m : C.meta) =
  match getMetaEntry m with
  | Unsolved ty -> ty
  | Solved (_, ty) -> ty

let resolveMeta (m : C.meta) =
  match getMetaEntry m with
  | Unsolved ty -> V.Stuck (V.Meta m, ty)
  | Solved (tr, _) -> tr