open import "prelude.ml" module S = import "data/set.ml" module M = import "data/map.ml" type expr = | Ref of string | App of expr * expr | Lam of string * expr | Case of expr * list (string * list string * expr) | Lit of int | Let of list (string * expr) * expr let app = curry App let lam = curry Lam let rec free_vars = function | Ref v -> S.singleton v | App (f, x) -> S.union (free_vars f) (free_vars x) | Lam (v, x) -> v `S.delete` free_vars x | Case (e, bs) -> bs |> map (fun (_, a, e) -> free_vars e `S.difference` S.from_list a) |> foldl S.union S.empty |> S.union (free_vars e) | Let (vs, b) -> let bound = S.from_list (map (fun (x, _) -> x) vs) vs |> map (fun (_, e) -> free_vars e) |> foldl S.union S.empty |> S.union (free_vars b) |> flip S.difference bound | Lit _ -> S.empty type hstype = | Tycon of string | Tyvar of string | Tyapp of hstype * hstype | Tyarr of hstype * hstype | Tytup of list hstype let rec arity = function | Tyarr (_, i) -> 1 + arity i | _ -> 0 type constr = Constr of string * list hstype type call_conv = Lua | Prim type fdecl = Fimport of { cc : call_conv, fent : string, ftype : hstype, var : string } type decl = | Decl of string * list string * expr | Data of string * list string * list constr | Foreign of fdecl type prog <- list decl