(* Copyright (c) 2008, Adam Chlipala
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * - Redistributions of source code must retain the above copyright notice,
 *   this list of conditions and the following disclaimer.
 * - Redistributions in binary form must reproduce the above copyright notice,
 *   this list of conditions and the following disclaimer in the documentation
 *   and/or other materials provided with the distribution.
 * - The names of contributors may not be used to endorse or promote products
 *   derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 *)

structure Corify :> CORIFY = struct

structure EM = ErrorMsg
structure L = Expl
structure L' = Core

structure IM = IntBinaryMap
structure SM = BinaryMapFn(struct
                           type ord_key = string
                           val compare = String.compare
                           end)

local
    val count = ref 0
in

fun reset v = count := v

fun alloc () =
    let
        val r = !count
    in
        count := r + 1;
        r
end

end

structure St : sig
    type t

    val empty : t

    val debug : t -> unit

    val enter : t -> t
    val leave : t -> {outer : t, inner : t}
    val ffi : string -> L'.con SM.map -> t

    datatype core_con =
             CNormal of int
           | CFfi of string
    val bindCon : t -> string -> int -> t * int
    val lookupConById : t -> int -> int option
    val lookupConByName : t -> string -> core_con

    val bindConstructor : t -> string -> int -> L'.patCon -> t
    val lookupConstructorByName : t -> string -> L'.patCon
    val lookupConstructorById : t -> int -> L'.patCon

    datatype core_val =
             ENormal of int
           | EFfi of string * L'.con
    val bindVal : t -> string -> int -> t * int
    val bindConstructorVal : t -> string -> int -> t
    val lookupValById : t -> int -> int option
    val lookupValByName : t -> string -> core_val

    val bindStr : t -> string -> int -> t -> t
    val lookupStrById : t -> int -> t
    val lookupStrByName : string * t -> t

    val bindFunctor : t -> string -> int -> string -> int -> L.str -> t
    val lookupFunctorById : t -> int -> string * int * L.str
    val lookupFunctorByName : string * t -> string * int * L.str
end = struct

datatype flattening =
         FNormal of {cons : int SM.map,
                     constructors : L'.patCon SM.map,
                     vals : int SM.map,
                     strs : flattening SM.map,
                     funs : (string * int * L.str) SM.map}
       | FFfi of {mod : string,
                  vals : L'.con SM.map}
                           
type t = {
     cons : int IM.map,
     constructors : L'.patCon IM.map,
     vals : int IM.map,
     strs : flattening IM.map,
     funs : (string * int * L.str) IM.map,
     current : flattening,
     nested : flattening list
}

val empty = {
    cons = IM.empty,
    constructors = IM.empty,
    vals = IM.empty,
    strs = IM.empty,
    funs = IM.empty,
    current = FNormal { cons = SM.empty, constructors = SM.empty, vals = SM.empty, strs = SM.empty, funs = SM.empty },
    nested = []
}

fun debug ({current = FNormal {cons, constructors, vals, strs, funs}, ...} : t) =
    print ("cons: " ^ Int.toString (SM.numItems cons) ^ "; "
           ^ "constructors: " ^ Int.toString (SM.numItems constructors) ^ "; "
           ^ "vals: " ^ Int.toString (SM.numItems vals) ^ "; "
           ^ "strs: " ^ Int.toString (SM.numItems strs) ^ "; "
           ^ "funs: " ^ Int.toString (SM.numItems funs) ^ "\n")
  | debug _ = print "Not normal!\n"

datatype core_con =
         CNormal of int
       | CFfi of string

datatype core_val =
         ENormal of int
       | EFfi of string * L'.con

fun bindCon {cons, constructors, vals, strs, funs, current, nested} s n =
    let
        val n' = alloc ()

        val current =
            case current of
                FFfi _ => raise Fail "Binding inside FFfi"
              | FNormal {cons, constructors, vals, strs, funs} =>
                FNormal {cons = SM.insert (cons, s, n'),
                         constructors = constructors,
                         vals = vals,
                         strs = strs,
                         funs = funs}
    in
        ({cons = IM.insert (cons, n, n'),
          constructors = constructors,
          vals = vals,
          strs = strs,
          funs = funs,
          current = current,
          nested = nested},
         n')
    end

fun lookupConById ({cons, ...} : t) n = IM.find (cons, n)

fun lookupConByName ({current, ...} : t) x =
    case current of
        FFfi {mod = m, ...} => CFfi m
      | FNormal {cons, ...} =>
        case SM.find (cons, x) of
            NONE => raise Fail "Corify.St.lookupConByName"
          | SOME n => CNormal n

fun bindVal {cons, constructors, vals, strs, funs, current, nested} s n =
    let
        val n' = alloc ()

        val current =
            case current of
                FFfi _ => raise Fail "Binding inside FFfi"
              | FNormal {cons, constructors, vals, strs, funs} =>
                FNormal {cons = cons,
                         constructors = constructors,
                         vals = SM.insert (vals, s, n'),
                         strs = strs,
                         funs = funs}
    in
        ({cons = cons,
          constructors = constructors,
          vals = IM.insert (vals, n, n'),
          strs = strs,
          funs = funs,
          current = current,
          nested = nested},
         n')
    end

fun bindConstructorVal {cons, constructors, vals, strs, funs, current, nested} s n =
    let
        val current =
            case current of
                FFfi _ => raise Fail "Binding inside FFfi"
              | FNormal {cons, constructors, vals, strs, funs} =>
                FNormal {cons = cons,
                         constructors = constructors,
                         vals = SM.insert (vals, s, n),
                         strs = strs,
                         funs = funs}
    in
        {cons = cons,
         constructors = constructors,
         vals = IM.insert (vals, n, n),
         strs = strs,
         funs = funs,
         current = current,
         nested = nested}
    end


fun lookupValById ({vals, ...} : t) n = IM.find (vals, n)

fun lookupValByName ({current, ...} : t) x =
    case current of
        FFfi {mod = m, vals, ...} =>
        (case SM.find (vals, x) of
             NONE => raise Fail "Corify.St.lookupValByName: no type for FFI val"
           | SOME t => EFfi (m, t))
      | FNormal {vals, ...} =>
        case SM.find (vals, x) of
            NONE => raise Fail "Corify.St.lookupValByName"
          | SOME n => ENormal n

fun bindConstructor {cons, constructors, vals, strs, funs, current, nested} s n n' =
    let
        val current =
            case current of
                FFfi _ => raise Fail "Binding inside FFfi"
              | FNormal {cons, constructors, vals, strs, funs} =>
                FNormal {cons = cons,
                         constructors = SM.insert (constructors, s, n'),
                         vals = vals,
                         strs = strs,
                         funs = funs}
    in
        {cons = cons,
         constructors = IM.insert (constructors, n, n'),
         vals = vals,
         strs = strs,
         funs = funs,
         current = current,
         nested = nested}
    end

fun lookupConstructorById ({constructors, ...} : t) n =
    case IM.find (constructors, n) of
        NONE => raise Fail "Corify.St.lookupConstructorById"
      | SOME x => x

fun lookupConstructorByName ({current, ...} : t) x =
    case current of
        FFfi {mod = m, ...} => L'.PConFfi (m, x)
      | FNormal {constructors, ...} =>
        case SM.find (constructors, x) of
            NONE => raise Fail "Corify.St.lookupConstructorByName"
          | SOME n => n

fun enter {cons, constructors, vals, strs, funs, current, nested} =
    {cons = cons,
     constructors = constructors,
     vals = vals,
     strs = strs,
     funs = funs,
     current = FNormal {cons = SM.empty,
                        constructors = SM.empty,
                        vals = SM.empty,
                        strs = SM.empty,
                        funs = SM.empty},
     nested = current :: nested}

fun dummy f = {cons = IM.empty,
               constructors = IM.empty,
               vals = IM.empty,
               strs = IM.empty,
               funs = IM.empty,
               current = f,
               nested = []}

fun leave {cons, constructors, vals, strs, funs, current, nested = m1 :: rest} =
        {outer = {cons = cons,
                  constructors = constructors,
                  vals = vals,
                  strs = strs,
                  funs = funs,
                  current = m1,
                  nested = rest},
         inner = dummy current}
  | leave _ = raise Fail "Corify.St.leave"

fun ffi m vals = dummy (FFfi {mod = m, vals = vals})

fun bindStr ({cons, constructors, vals, strs, funs,
              current = FNormal {cons = mcons, constructors = mconstructors,
                                 vals = mvals, strs = mstrs, funs = mfuns}, nested} : t)
            x n ({current = f, ...} : t) =
    {cons = cons,
     constructors = constructors,
     vals = vals,
     strs = IM.insert (strs, n, f),
     funs = funs,
     current = FNormal {cons = mcons,
                        constructors = mconstructors,
                        vals = mvals,
                        strs = SM.insert (mstrs, x, f),
                        funs = mfuns},
     nested = nested}
  | bindStr _ _ _ _ = raise Fail "Corify.St.bindStr"

fun lookupStrById ({strs, ...} : t) n =
    case IM.find (strs, n) of
        NONE => raise Fail "Corify.St.lookupStrById"
      | SOME f => dummy f

fun lookupStrByName (m, {current = FNormal {strs, ...}, ...} : t) =
    (case SM.find (strs, m) of
         NONE => raise Fail "Corify.St.lookupStrByName"
       | SOME f => dummy f)
  | lookupStrByName _ = raise Fail "Corify.St.lookupStrByName"

fun bindFunctor ({cons, constructors, vals, strs, funs,
                  current = FNormal {cons = mcons, constructors = mconstructors,
                                     vals = mvals, strs = mstrs, funs = mfuns}, nested} : t)
                x n xa na str =
    {cons = cons,
     constructors = constructors,
     vals = vals,
     strs = strs,
     funs = IM.insert (funs, n, (xa, na, str)),
     current = FNormal {cons = mcons,
                        constructors = mconstructors,
                        vals = mvals,
                        strs = mstrs,
                        funs = SM.insert (mfuns, x, (xa, na, str))},
     nested = nested}
  | bindFunctor _ _ _ _ _ _ = raise Fail "Corify.St.bindFunctor"

fun lookupFunctorById ({funs, ...} : t) n =
    case IM.find (funs, n) of
        NONE => raise Fail "Corify.St.lookupFunctorById"
      | SOME v => v

fun lookupFunctorByName (m, {current = FNormal {funs, ...}, ...} : t) =
    (case SM.find (funs, m) of
         NONE => raise Fail "Corify.St.lookupFunctorByName"
       | SOME v => v)
  | lookupFunctorByName _ = raise Fail "Corify.St.lookupFunctorByName"

end


fun corifyKind (k, loc) =
    case k of
        L.KType => (L'.KType, loc)
      | L.KArrow (k1, k2) => (L'.KArrow (corifyKind k1, corifyKind k2), loc)
      | L.KName => (L'.KName, loc)
      | L.KRecord k => (L'.KRecord (corifyKind k), loc)
      | L.KUnit => (L'.KUnit, loc)

fun corifyCon st (c, loc) =
    case c of
        L.TFun (t1, t2) => (L'.TFun (corifyCon st t1, corifyCon st t2), loc)
      | L.TCFun (x, k, t) => (L'.TCFun (x, corifyKind k, corifyCon st t), loc)
      | L.TRecord c => (L'.TRecord (corifyCon st c), loc)

      | L.CRel n => (L'.CRel n, loc)
      | L.CNamed n =>
        (case St.lookupConById st n of
             NONE => (L'.CNamed n, loc)
           | SOME n => (L'.CNamed n, loc))
      | L.CModProj (m, ms, x) =>
        let
            val st = St.lookupStrById st m
            val st = foldl St.lookupStrByName st ms
        in
            case St.lookupConByName st x of
                St.CNormal n => (L'.CNamed n, loc)
              | St.CFfi m => (L'.CFfi (m, x), loc)
        end

      | L.CApp (c1, c2) => (L'.CApp (corifyCon st c1, corifyCon st c2), loc)
      | L.CAbs (x, k, c) => (L'.CAbs (x, corifyKind k, corifyCon st c), loc)

      | L.CName s => (L'.CName s, loc)

      | L.CRecord (k, xcs) =>
        (L'.CRecord (corifyKind k, map (fn (c1, c2) => (corifyCon st c1, corifyCon st c2)) xcs), loc)
      | L.CConcat (c1, c2) => (L'.CConcat (corifyCon st c1, corifyCon st c2), loc)
      | L.CFold (k1, k2) => (L'.CFold (corifyKind k1, corifyKind k2), loc)
      | L.CUnit => (L'.CUnit, loc)

fun corifyPatCon st pc =
    case pc of
        L.PConVar n => St.lookupConstructorById st n
      | L.PConProj (m1, ms, x) =>
        let
            val st = St.lookupStrById st m1
            val st = foldl St.lookupStrByName st ms
        in
            St.lookupConstructorByName st x
        end

fun corifyPat st (p, loc) =
    case p of
        L.PWild => (L'.PWild, loc)
      | L.PVar x => (L'.PVar x, loc)
      | L.PPrim p => (L'.PPrim p, loc)
      | L.PCon (pc, po) => (L'.PCon (corifyPatCon st pc, Option.map (corifyPat st) po), loc)
      | L.PRecord xps => (L'.PRecord (map (fn (x, p) => (x, corifyPat st p)) xps), loc)

fun corifyExp st (e, loc) =
    case e of
        L.EPrim p => (L'.EPrim p, loc)
      | L.ERel n => (L'.ERel n, loc)
      | L.ENamed n =>
        (case St.lookupValById st n of
             NONE => (L'.ENamed n, loc)
           | SOME n => (L'.ENamed n, loc))
      | L.EModProj (m, ms, x) =>
        let
            val st = St.lookupStrById st m
            val st = foldl St.lookupStrByName st ms
        in
            case St.lookupValByName st x of
                St.ENormal n => (L'.ENamed n, loc)
              | St.EFfi (m, t) =>
                case t of
                    (L'.TFun (dom as (L'.TRecord (L'.CRecord (_, []), _), _), ran), _) =>
                    (L'.EAbs ("arg", dom, ran, (L'.EFfiApp (m, x, []), loc)), loc)
                  | t as (L'.TFun _, _) =>
                    let
                        fun getArgs (all as (t, _), args) =
                            case t of
                                L'.TFun (dom, ran) => getArgs (ran, dom :: args)
                              | _ => (all, rev args)
                                     
                        val (result, args) = getArgs (t, [])

                        val (actuals, _) = foldr (fn (_, (actuals, n)) =>
                                                     ((L'.ERel n, loc) :: actuals,
                                                      n + 1)) ([], 0) args
                        val app = (L'.EFfiApp (m, x, actuals), loc)
                        val (abs, _, _) = foldr (fn (t, (abs, ran, n)) =>
                                                    ((L'.EAbs ("arg" ^ Int.toString n,
                                                               t,
                                                               ran,
                                                               abs), loc),
                                                     (L'.TFun (t, ran), loc),
                                                     n - 1)) (app, result, length args - 1) args
                    in
                        abs
                    end
                  | _ => (L'.EFfi (m, x), loc)
        end
      | L.EApp (e1, e2) => (L'.EApp (corifyExp st e1, corifyExp st e2), loc)
      | L.EAbs (x, dom, ran, e1) => (L'.EAbs (x, corifyCon st dom, corifyCon st ran, corifyExp st e1), loc)
      | L.ECApp (e1, c) => (L'.ECApp (corifyExp st e1, corifyCon st c), loc)
      | L.ECAbs (x, k, e1) => (L'.ECAbs (x, corifyKind k, corifyExp st e1), loc)

      | L.ERecord xes => (L'.ERecord (map (fn (c, e, t) =>
                                              (corifyCon st c, corifyExp st e, corifyCon st t)) xes), loc)
      | L.EField (e1, c, {field, rest}) => (L'.EField (corifyExp st e1, corifyCon st c,
                                                       {field = corifyCon st field, rest = corifyCon st rest}), loc)
      | L.ECut (e1, c, {field, rest}) => (L'.ECut (corifyExp st e1, corifyCon st c,
                                                   {field = corifyCon st field, rest = corifyCon st rest}), loc)
      | L.EFold k => (L'.EFold (corifyKind k), loc)

      | L.ECase (e, pes, t) => (L'.ECase (corifyExp st e,
                                          map (fn (p, e) => (corifyPat st p, corifyExp st e)) pes,
                                          corifyCon st t),
                                loc)

      | L.EWrite e => (L'.EWrite (corifyExp st e), loc)

fun corifyDecl ((d, loc : EM.span), st) =
    case d of
        L.DCon (x, n, k, c) =>
        let
            val (st, n) = St.bindCon st x n
        in
            ([(L'.DCon (x, n, corifyKind k, corifyCon st c), loc)], st)
        end
      | L.DDatatype (x, n, xncs) =>
        let
            val (st, n) = St.bindCon st x n
            val (xncs, st) = ListUtil.foldlMap (fn ((x, n, co), st) =>
                                                   let
                                                       val st = St.bindConstructor st x n (L'.PConVar n)
                                                       val st = St.bindConstructorVal st x n
                                                       val co = Option.map (corifyCon st) co
                                                   in
                                                       ((x, n, co), st)
                                                   end) st xncs

            val t = (L'.CNamed n, loc)
            val dcons = map (fn (x, n, to) =>
                                let
                                    val (e, t) =
                                        case to of
                                            NONE => ((L'.ECon (n, NONE), loc), t)
                                          | SOME t' => ((L'.EAbs ("x", t', t,
                                                                  (L'.ECon (n, SOME (L'.ERel 0, loc)), loc)),
                                                         loc),
                                                        (L'.TFun (t', t), loc))
                                in
                                    (L'.DVal (x, n, t, e, ""), loc)
                                end) xncs
        in
            ((L'.DDatatype (x, n, xncs), loc) :: dcons, st)
        end
      | L.DDatatypeImp (x, n, m1, ms, s, xncs) =>
        let
            val (st, n) = St.bindCon st x n
            val c = corifyCon st (L.CModProj (m1, ms, s), loc)

            val m = foldl (fn (x, m) => (L.StrProj (m, x), loc)) (L.StrVar m1, loc) ms
            val (_, {inner, ...}) = corifyStr (m, st)

            val (xncs, st) = ListUtil.foldlMap (fn ((x, n, co), st) =>
                                                   let
                                                       val n' = St.lookupConstructorByName inner x
                                                       val st = St.bindConstructor st x n n'
                                                       val (st, n) = St.bindVal st x n
                                                       val co = Option.map (corifyCon st) co
                                                   in
                                                       ((x, n, co), st)
                                                   end) st xncs
                             
            val cds = map (fn (x, n, co) =>
                              let
                                  val t = case co of
                                              NONE => c
                                            | SOME t' => (L'.TFun (t', c), loc)
                                  val e = corifyExp st (L.EModProj (m1, ms, x), loc)
                              in
                                  (L'.DVal (x, n, t, e, x), loc)
                              end) xncs
        in
            ((L'.DCon (x, n, (L'.KType, loc), c), loc) :: cds, st)
        end
      | L.DVal (x, n, t, e) =>
        let
            val (st, n) = St.bindVal st x n
            val s =
                if String.isPrefix "wrap_" x then
                    String.extract (x, 5, NONE)
                else
                    x
        in
            ([(L'.DVal (x, n, corifyCon st t, corifyExp st e, s), loc)], st)
        end
      | L.DValRec vis =>
        let
            val (vis, st) = ListUtil.foldlMap
                                (fn ((x, n, t, e), st) =>
                                    let
                                        val (st, n) = St.bindVal st x n
                                    in
                                        ((x, n, t, e), st)
                                    end)
                                st vis

            val vis = map
                          (fn (x, n, t, e) =>
                              let
                                  val s =
                                      if String.isPrefix "wrap_" x then
                                          String.extract (x, 5, NONE)
                                      else
                                          x
                              in
                                  (x, n, corifyCon st t, corifyExp st e, s)
                              end)
                          vis
        in
            ([(L'.DValRec vis, loc)], st)
        end
      | L.DSgn _ => ([], st)

      | L.DStr (x, n, _, (L.StrFun (xa, na, _, _, str), _)) =>
        ([], St.bindFunctor st x n xa na str)

      | L.DStr (x, n, _, str) =>
        let
            val (ds, {inner, outer}) = corifyStr (str, st)
            val st = St.bindStr outer x n inner
        in
            (ds, st)
        end

      | L.DFfiStr (m, n, (sgn, _)) =>
        (case sgn of
             L.SgnConst sgis =>
             let
                 val (ds, cmap, st) =
                     foldl (fn ((sgi, _), (ds, cmap, st)) =>
                               case sgi of
                                   L.SgiConAbs (x, n, k) =>
                                   let
                                       val (st, n') = St.bindCon st x n
                                   in
                                       ((L'.DCon (x, n', corifyKind k, (L'.CFfi (m, x), loc)), loc) :: ds,
                                        cmap,
                                        st)
                                   end
                                 | L.SgiCon (x, n, k, _) =>
                                   let
                                       val (st, n') = St.bindCon st x n
                                   in
                                       ((L'.DCon (x, n', corifyKind k, (L'.CFfi (m, x), loc)), loc) :: ds,
                                        cmap,
                                        st)
                                   end

                                 | L.SgiVal (x, _, c) =>
                                   (ds,
                                    SM.insert (cmap, x, corifyCon st c),
                                    st)
                                 | _ => (ds, cmap, st)) ([], SM.empty, st) sgis

                 val st = St.bindStr st m n (St.ffi m cmap)
             in
                 (rev ds, st)
             end
           | _ => raise Fail "Non-const signature for FFI structure")

      | L.DExport (en, sgn, str) =>
        (case #1 sgn of
             L.SgnConst sgis =>
             let
                 fun pathify (str, _) =
                     case str of
                         L.StrVar m => SOME (m, [])
                       | L.StrProj (str, s) =>
                         Option.map (fn (m, ms) => (m, ms @ [s])) (pathify str)
                       | _ => NONE
             in
                 case pathify str of
                     NONE => (ErrorMsg.errorAt loc "Structure is too fancy to export";
                              ([], st))
                   | SOME (m, ms) =>
                     let
                         fun wrapSgi ((sgi, _), (wds, eds))  =
                             case sgi of
                                 L.SgiVal (s, _, t as (L.TFun (dom, ran), _)) =>
                                 (case (#1 dom, #1 ran) of
                                      (L.TRecord (L.CRecord (_, []), _),
                                       L.CApp
                                           ((L.CApp
                                                 ((L.CApp ((L.CModProj (_, [], "xml"), _),
                                                           (L.CRecord (_, [((L.CName "Html", _),
                                                                            _)]), _)), _), _), _), _)) =>
                                      let
                                          val ran = (L.TRecord (L.CRecord ((L.KType, loc), []), loc), loc)
                                          val e = (L.EModProj (m, ms, s), loc)
                                          val e = (L.EAbs ("vs", dom, ran,
                                                           (L.EWrite (L.EApp (e, (L.ERel 0, loc)), loc), loc)), loc)
                                      in
                                          ((L.DVal ("wrap_" ^ s, 0,
                                                    (L.TFun (dom, ran), loc),
                                                    e), loc) :: wds,
                                           (fn st =>
                                               case #1 (corifyExp st (L.EModProj (en, [], "wrap_" ^ s), loc)) of
                                                   L'.ENamed n => (L'.DExport (L'.Link, n), loc)
                                                 | _ => raise Fail "Corify: Value to export didn't corify properly")
                                           :: eds)
                                      end
                                    | _ => (wds, eds))
                               | _ => (wds, eds)

                         val (wds, eds) = foldl wrapSgi ([], []) sgis
                         val wrapper = (L.StrConst wds, loc)
                         val (ds, {inner, outer}) = corifyStr (wrapper, st)
                         val st = St.bindStr outer "wrapper" en inner
                         
                         val ds = ds @ map (fn f => f st) eds
                     in
                         (ds, st)
                     end
             end
           | _ => raise Fail "Non-const signature for 'export'")

and corifyStr ((str, _), st) =
    case str of
        L.StrConst ds =>
        let
            val st = St.enter st
            val (ds, st) = ListUtil.foldlMapConcat corifyDecl st ds
        in
            (ds, St.leave st)
        end
      | L.StrVar n => ([], {inner = St.lookupStrById st n, outer = st})
      | L.StrProj (str, x) =>
        let
            val (ds, {inner, outer}) = corifyStr (str, st)
        in
            (ds, {inner = St.lookupStrByName (x, inner), outer = outer})
        end
      | L.StrFun _ => raise Fail "Corify of nested functor definition"
      | L.StrApp (str1, str2) =>
        let
            fun unwind' (str, _) =
                case str of
                    L.StrVar n => St.lookupStrById st n
                  | L.StrProj (str, x) => St.lookupStrByName (x, unwind' str)
                  | _ => raise Fail "Corify of fancy functor application [1]"

            fun unwind (str, _) =
                case str of
                    L.StrVar n => St.lookupFunctorById st n
                  | L.StrProj (str, x) => St.lookupFunctorByName (x, unwind' str)
                  | _ => raise Fail "Corify of fancy functor application [2]"

            val (xa, na, body) = unwind str1

            val (ds1, {inner = inner', outer}) = corifyStr (str2, st)
            val (ds2, {inner, outer}) = corifyStr (body, St.bindStr outer xa na inner')
        in
            (ds1 @ ds2, {inner = St.bindStr inner xa na inner', outer = outer})
        end

fun maxName ds = foldl (fn ((d, _), n) =>
                           case d of
                               L.DCon (_, n', _, _) => Int.max (n, n')
                             | L.DDatatype (_, n', _) => Int.max (n, n')
                             | L.DDatatypeImp (_, n', _, _, _, _) => Int.max (n, n')
                             | L.DVal (_, n', _, _) => Int.max (n, n')
                             | L.DValRec vis => foldl (fn ((_, n', _, _), n) => Int.max (n, n)) n vis
                             | L.DSgn (_, n', _) => Int.max (n, n')
                             | L.DStr (_, n', _, str) => Int.max (n, Int.max (n', maxNameStr str))
                             | L.DFfiStr (_, n', _) => Int.max (n, n')
                             | L.DExport _ => n)
                 0 ds

and maxNameStr (str, _) =
    case str of
        L.StrConst ds => maxName ds
      | L.StrVar n => n
      | L.StrProj (str, _) => maxNameStr str
      | L.StrFun (_, _, _, _, str) => maxNameStr str
      | L.StrApp (str1, str2) => Int.max (maxNameStr str1, maxNameStr str2)

fun corify ds =
    let
        val () = reset (maxName ds + 1)

        val (ds, _) = ListUtil.foldlMapConcat corifyDecl St.empty ds
    in
        ds
    end

end