adamc@2: (* Copyright (c) 2008, Adam Chlipala
adamc@2:  * All rights reserved.
adamc@2:  *
adamc@2:  * Redistribution and use in source and binary forms, with or without
adamc@2:  * modification, are permitted provided that the following conditions are met:
adamc@2:  *
adamc@2:  * - Redistributions of source code must retain the above copyright notice,
adamc@2:  *   this list of conditions and the following disclaimer.
adamc@2:  * - Redistributions in binary form must reproduce the above copyright notice,
adamc@2:  *   this list of conditions and the following disclaimer in the documentation
adamc@2:  *   and/or other materials provided with the distribution.
adamc@2:  * - The names of contributors may not be used to endorse or promote products
adamc@2:  *   derived from this software without specific prior written permission.
adamc@2:  *
adamc@2:  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
adamc@2:  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
adamc@2:  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
adamc@2:  * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
adamc@2:  * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 
adamc@2:  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
adamc@2:  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
adamc@2:  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
adamc@2:  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
adamc@2:  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
adamc@2:  * POSSIBILITY OF SUCH DAMAGE.
adamc@2:  *)
adamc@2: 
adamc@2: structure Elaborate :> ELABORATE = struct
adamc@2: 
adamc@14: structure P = Prim
adamc@4: structure L = Source
adamc@2: structure L' = Elab
adamc@2: structure E = ElabEnv
adamc@2: structure U = ElabUtil
adamc@2: 
adamc@3: open Print
adamc@3: open ElabPrint
adamc@3: 
adamc@2: fun elabExplicitness e =
adamc@2:     case e of
adamc@2:         L.Explicit => L'.Explicit
adamc@2:       | L.Implicit => L'.Implicit
adamc@2: 
adamc@2: fun occursKind r =
adamc@2:     U.Kind.exists (fn L'.KUnif (_, r') => r = r'
adamc@2:                     | _ => false)
adamc@2: 
adamc@3: datatype kunify_error =
adamc@2:          KOccursCheckFailed of L'.kind * L'.kind
adamc@2:        | KIncompatible of L'.kind * L'.kind
adamc@2: 
adamc@3: exception KUnify' of kunify_error
adamc@3: 
adamc@3: fun kunifyError err =
adamc@2:     case err of
adamc@2:         KOccursCheckFailed (k1, k2) =>
adamc@3:         eprefaces "Kind occurs check failed"
adamc@3:         [("Kind 1", p_kind k1),
adamc@3:          ("Kind 2", p_kind k2)]
adamc@2:       | KIncompatible (k1, k2) =>
adamc@3:         eprefaces "Incompatible kinds"
adamc@3:         [("Kind 1", p_kind k1),
adamc@3:          ("Kind 2", p_kind k2)]
adamc@2: 
adamc@3: fun unifyKinds' (k1All as (k1, _)) (k2All as (k2, _)) =
adamc@2:     let
adamc@3:         fun err f = raise KUnify' (f (k1All, k2All))
adamc@2:     in
adamc@2:         case (k1, k2) of
adamc@2:             (L'.KType, L'.KType) => ()
adamc@2:           | (L'.KArrow (d1, r1), L'.KArrow (d2, r2)) =>
adamc@3:             (unifyKinds' d1 d2;
adamc@3:              unifyKinds' r1 r2)
adamc@2:           | (L'.KName, L'.KName) => ()
adamc@3:           | (L'.KRecord k1, L'.KRecord k2) => unifyKinds' k1 k2
adamc@2: 
adamc@2:           | (L'.KError, _) => ()
adamc@2:           | (_, L'.KError) => ()
adamc@2: 
adamc@3:           | (L'.KUnif (_, ref (SOME k1All)), _) => unifyKinds' k1All k2All
adamc@3:           | (_, L'.KUnif (_, ref (SOME k2All))) => unifyKinds' k1All k2All
adamc@2: 
adamc@2:           | (L'.KUnif (_, r1), L'.KUnif (_, r2)) =>
adamc@2:             if r1 = r2 then
adamc@2:                 ()
adamc@2:             else
adamc@2:                 r1 := SOME k2All
adamc@2: 
adamc@2:           | (L'.KUnif (_, r), _) =>
adamc@2:             if occursKind r k2All then
adamc@2:                 err KOccursCheckFailed
adamc@2:             else
adamc@2:                 r := SOME k2All
adamc@2:           | (_, L'.KUnif (_, r)) =>
adamc@2:             if occursKind r k1All then
adamc@2:                 err KOccursCheckFailed
adamc@2:             else
adamc@2:                 r := SOME k1All
adamc@2: 
adamc@2:           | _ => err KIncompatible
adamc@2:     end
adamc@2: 
adamc@3: exception KUnify of L'.kind * L'.kind * kunify_error
adamc@3: 
adamc@3: fun unifyKinds k1 k2 =
adamc@3:     unifyKinds' k1 k2
adamc@3:     handle KUnify' err => raise KUnify (k1, k2, err)
adamc@3: 
adamc@3: datatype con_error =
adamc@3:          UnboundCon of ErrorMsg.span * string
adamc@3:        | WrongKind of L'.con * L'.kind * L'.kind * kunify_error
adamc@3: 
adamc@5: fun conError env err =
adamc@3:     case err of
adamc@3:         UnboundCon (loc, s) =>
adamc@3:         ErrorMsg.errorAt loc ("Unbound constructor variable " ^ s)
adamc@3:       | WrongKind (c, k1, k2, kerr) =>
adamc@3:         (ErrorMsg.errorAt (#2 c) "Wrong kind";
adamc@5:          eprefaces' [("Constructor", p_con env c),
adamc@5:                      ("Have kind", p_kind k1),
adamc@5:                      ("Need kind", p_kind k2)];
adamc@3:          kunifyError kerr)
adamc@3: 
adamc@5: fun checkKind env c k1 k2 =
adamc@3:     unifyKinds k1 k2
adamc@3:     handle KUnify (k1, k2, err) =>
adamc@5:            conError env (WrongKind (c, k1, k2, err))
adamc@3: 
adamc@3: val dummy = ErrorMsg.dummySpan
adamc@3: 
adamc@3: val ktype = (L'.KType, dummy)
adamc@3: val kname = (L'.KName, dummy)
adamc@12: val ktype_record = (L'.KRecord ktype, dummy)
adamc@3: 
adamc@3: val cerror = (L'.CError, dummy)
adamc@3: val kerror = (L'.KError, dummy)
adamc@10: val eerror = (L'.EError, dummy)
adamc@3: 
adamc@3: local
adamc@3:     val count = ref 0
adamc@3: in
adamc@3: 
adamc@3: fun resetKunif () = count := 0
adamc@3: 
adamc@3: fun kunif () =
adamc@3:     let
adamc@3:         val n = !count
adamc@3:         val s = if n <= 26 then
adamc@3:                     str (chr (ord #"A" + n))
adamc@3:                 else
adamc@3:                     "U" ^ Int.toString (n - 26)
adamc@3:     in
adamc@3:         count := n + 1;
adamc@3:         (L'.KUnif (s, ref NONE), dummy)
adamc@3:     end
adamc@3: 
adamc@3: end
adamc@3: 
adamc@10: local
adamc@10:     val count = ref 0
adamc@10: in
adamc@10: 
adamc@10: fun resetCunif () = count := 0
adamc@10: 
adamc@10: fun cunif k =
adamc@10:     let
adamc@10:         val n = !count
adamc@10:         val s = if n <= 26 then
adamc@10:                     str (chr (ord #"A" + n))
adamc@10:                 else
adamc@10:                     "U" ^ Int.toString (n - 26)
adamc@10:     in
adamc@10:         count := n + 1;
adamc@10:         (L'.CUnif (k, s, ref NONE), dummy)
adamc@10:     end
adamc@10: 
adamc@10: end
adamc@10: 
adamc@18: fun elabKind (k, loc) =
adamc@18:     case k of
adamc@18:         L.KType => (L'.KType, loc)
adamc@18:       | L.KArrow (k1, k2) => (L'.KArrow (elabKind k1, elabKind k2), loc)
adamc@18:       | L.KName => (L'.KName, loc)
adamc@18:       | L.KRecord k => (L'.KRecord (elabKind k), loc)
adamc@18:       | L.KWild => kunif ()
adamc@18: 
adamc@3: fun elabCon env (c, loc) =
adamc@3:     case c of
adamc@3:         L.CAnnot (c, k) =>
adamc@3:         let
adamc@3:             val k' = elabKind k
adamc@3:             val (c', ck) = elabCon env c
adamc@3:         in
adamc@5:             checkKind env c' ck k';
adamc@3:             (c', k')
adamc@3:         end
adamc@3: 
adamc@3:       | L.TFun (t1, t2) =>
adamc@3:         let
adamc@3:             val (t1', k1) = elabCon env t1
adamc@3:             val (t2', k2) = elabCon env t2
adamc@3:         in
adamc@5:             checkKind env t1' k1 ktype;
adamc@5:             checkKind env t2' k2 ktype;
adamc@3:             ((L'.TFun (t1', t2'), loc), ktype)
adamc@3:         end
adamc@3:       | L.TCFun (e, x, k, t) =>
adamc@3:         let
adamc@3:             val e' = elabExplicitness e
adamc@3:             val k' = elabKind k
adamc@3:             val env' = E.pushCRel env x k'
adamc@3:             val (t', tk) = elabCon env' t
adamc@3:         in
adamc@5:             checkKind env t' tk ktype;
adamc@3:             ((L'.TCFun (e', x, k', t'), loc), ktype)
adamc@3:         end
adamc@3:       | L.TRecord c =>
adamc@3:         let
adamc@3:             val (c', ck) = elabCon env c
adamc@3:             val k = (L'.KRecord ktype, loc)
adamc@3:         in
adamc@5:             checkKind env c' ck k;
adamc@3:             ((L'.TRecord c', loc), ktype)
adamc@3:         end
adamc@3: 
adamc@3:       | L.CVar s =>
adamc@3:         (case E.lookupC env s of
adamc@9:              E.NotBound =>
adamc@5:              (conError env (UnboundCon (loc, s));
adamc@3:               (cerror, kerror))
adamc@9:            | E.Rel (n, k) =>
adamc@3:              ((L'.CRel n, loc), k)
adamc@9:            | E.Named (n, k) =>
adamc@3:              ((L'.CNamed n, loc), k))
adamc@3:       | L.CApp (c1, c2) =>
adamc@3:         let
adamc@3:             val (c1', k1) = elabCon env c1
adamc@3:             val (c2', k2) = elabCon env c2
adamc@3:             val dom = kunif ()
adamc@3:             val ran = kunif ()
adamc@3:         in
adamc@5:             checkKind env c1' k1 (L'.KArrow (dom, ran), loc);
adamc@5:             checkKind env c2' k2 dom;
adamc@3:             ((L'.CApp (c1', c2'), loc), ran)
adamc@3:         end
adamc@8:       | L.CAbs (x, k, t) =>
adamc@3:         let
adamc@3:             val k' = elabKind k
adamc@3:             val env' = E.pushCRel env x k'
adamc@3:             val (t', tk) = elabCon env' t
adamc@3:         in
adamc@8:             ((L'.CAbs (x, k', t'), loc),
adamc@3:              (L'.KArrow (k', tk), loc))
adamc@3:         end
adamc@3: 
adamc@3:       | L.CName s =>
adamc@3:         ((L'.CName s, loc), kname)
adamc@3: 
adamc@3:       | L.CRecord xcs =>
adamc@3:         let
adamc@3:             val k = kunif ()
adamc@3: 
adamc@3:             val xcs' = map (fn (x, c) =>
adamc@3:                                let
adamc@3:                                    val (x', xk) = elabCon env x
adamc@3:                                    val (c', ck) = elabCon env c
adamc@3:                                in
adamc@5:                                    checkKind env x' xk kname;
adamc@5:                                    checkKind env c' ck k;
adamc@3:                                    (x', c')
adamc@3:                                end) xcs
adamc@3:         in
adamc@5:             ((L'.CRecord (k, xcs'), loc), (L'.KRecord k, loc))
adamc@3:         end
adamc@3:       | L.CConcat (c1, c2) =>
adamc@3:         let
adamc@3:             val (c1', k1) = elabCon env c1
adamc@3:             val (c2', k2) = elabCon env c2
adamc@3:             val ku = kunif ()
adamc@3:             val k = (L'.KRecord ku, loc)
adamc@3:         in
adamc@5:             checkKind env c1' k1 k;
adamc@5:             checkKind env c2' k2 k;
adamc@3:             ((L'.CConcat (c1', c2'), loc), k)
adamc@3:         end
adamc@3: 
adamc@18:       | L.CWild k =>
adamc@18:         let
adamc@18:             val k' = elabKind k
adamc@18:         in
adamc@18:             (cunif k', k')
adamc@18:         end
adamc@18: 
adamc@6: fun kunifsRemain k =
adamc@6:     case k of
adamc@6:         L'.KUnif (_, ref NONE) => true
adamc@6:       | _ => false
adamc@10: fun cunifsRemain c =
adamc@10:     case c of
adamc@10:         L'.CUnif (_, _, ref NONE) => true
adamc@10:       | _ => false
adamc@6: 
adamc@6: val kunifsInKind = U.Kind.exists kunifsRemain
adamc@6: val kunifsInCon = U.Con.exists {kind = kunifsRemain,
adamc@6:                                 con = fn _ => false}
adamc@10: val kunifsInExp = U.Exp.exists {kind = kunifsRemain,
adamc@10:                                 con = fn _ => false,
adamc@10:                                 exp = fn _ => false}
adamc@10: 
adamc@10: val cunifsInCon = U.Con.exists {kind = fn _ => false,
adamc@10:                                 con = cunifsRemain}
adamc@10: val cunifsInExp = U.Exp.exists {kind = fn _ => false,
adamc@10:                                 con = cunifsRemain,
adamc@10:                                 exp = fn _ => false}
adamc@10: 
adamc@10: fun occursCon r =
adamc@10:     U.Con.exists {kind = fn _ => false,
adamc@10:                   con = fn L'.CUnif (_, _, r') => r = r'
adamc@10:                          | _ => false}
adamc@10: 
adamc@10: datatype cunify_error =
adamc@10:          CKind of L'.kind * L'.kind * kunify_error
adamc@10:        | COccursCheckFailed of L'.con * L'.con
adamc@10:        | CIncompatible of L'.con * L'.con
adamc@10:        | CExplicitness of L'.con * L'.con
adamc@12:        | CKindof of L'.con
adamc@12:        | CRecordFailure
adamc@10: 
adamc@10: exception CUnify' of cunify_error
adamc@10: 
adamc@10: fun cunifyError env err =
adamc@10:     case err of
adamc@10:         CKind (k1, k2, kerr) =>
adamc@10:         (eprefaces "Kind unification failure"
adamc@10:                    [("Kind 1", p_kind k1),
adamc@10:                     ("Kind 2", p_kind k2)];
adamc@10:          kunifyError kerr)
adamc@10:       | COccursCheckFailed (c1, c2) =>
adamc@10:         eprefaces "Constructor occurs check failed"
adamc@10:                   [("Con 1", p_con env c1),
adamc@10:                    ("Con 2", p_con env c2)]
adamc@10:       | CIncompatible (c1, c2) =>
adamc@10:         eprefaces "Incompatible constructors"
adamc@10:                   [("Con 1", p_con env c1),
adamc@10:                    ("Con 2", p_con env c2)]
adamc@10:       | CExplicitness (c1, c2) =>
adamc@10:         eprefaces "Differing constructor function explicitness"
adamc@10:                   [("Con 1", p_con env c1),
adamc@10:                    ("Con 2", p_con env c2)]
adamc@12:       | CKindof c =>
adamc@12:         eprefaces "Kind unification variable blocks kindof calculation"
adamc@12:                   [("Con", p_con env c)]
adamc@12:       | CRecordFailure =>
adamc@12:         eprefaces "Can't unify record constructors" []
adamc@10: 
adamc@13: exception SynUnif = E.SynUnif
adamc@13: val liftConInCon = E.liftConInCon
adamc@12: 
adamc@12: val subConInCon =
adamc@12:     U.Con.mapB {kind = fn k => k,
adamc@12:                 con = fn (xn, rep) => fn c =>
adamc@12:                                   case c of
adamc@12:                                       L'.CRel xn' =>
adamc@12:                                       if xn = xn' then
adamc@12:                                           #1 rep
adamc@12:                                       else
adamc@12:                                           c
adamc@17:                                     (*| L'.CUnif _ => raise SynUnif*)
adamc@12:                                     | _ => c,
adamc@12:                 bind = fn ((xn, rep), U.Con.Rel _) => (xn+1, liftConInCon 0 rep)
adamc@12:                         | (ctx, _) => ctx}
adamc@12: 
adamc@12: type record_summary = {
adamc@12:      fields : (L'.con * L'.con) list,
adamc@12:      unifs : (L'.con * L'.con option ref) list,
adamc@12:      others : L'.con list
adamc@12: }
adamc@12: 
adamc@12: fun summaryToCon {fields, unifs, others} =
adamc@12:     let
adamc@12:         val c = (L'.CRecord (ktype, []), dummy)
adamc@12:         val c = List.foldr (fn (c', c) => (L'.CConcat (c', c), dummy)) c others
adamc@12:         val c = List.foldr (fn ((c', _), c) => (L'.CConcat (c', c), dummy)) c unifs
adamc@12:     in
adamc@12:         (L'.CConcat ((L'.CRecord (ktype, fields), dummy), c), dummy)
adamc@12:     end
adamc@12: 
adamc@12: fun p_summary env s = p_con env (summaryToCon s)
adamc@12: 
adamc@12: exception CUnify of L'.con * L'.con * cunify_error
adamc@12: 
adamc@12: fun hnormKind (kAll as (k, _)) =
adamc@12:     case k of
adamc@12:         L'.KUnif (_, ref (SOME k)) => hnormKind k
adamc@12:       | _ => kAll
adamc@12: 
adamc@12: fun kindof env (c, loc) =
adamc@12:     case c of
adamc@12:         L'.TFun _ => ktype
adamc@12:       | L'.TCFun _ => ktype
adamc@12:       | L'.TRecord _ => ktype
adamc@12: 
adamc@12:       | L'.CRel xn => #2 (E.lookupCRel env xn)
adamc@12:       | L'.CNamed xn => #2 (E.lookupCNamed env xn)
adamc@12:       | L'.CApp (c, _) =>
adamc@12:         (case #1 (hnormKind (kindof env c)) of
adamc@12:              L'.KArrow (_, k) => k
adamc@12:            | L'.KError => kerror
adamc@12:            | _ => raise CUnify' (CKindof c))
adamc@12:       | L'.CAbs (x, k, c) => (L'.KArrow (k, kindof (E.pushCRel env x k) c), loc)
adamc@12: 
adamc@12:       | L'.CName _ => kname
adamc@12: 
adamc@12:       | L'.CRecord (k, _) => (L'.KRecord k, loc)
adamc@12:       | L'.CConcat (c, _) => kindof env c
adamc@12: 
adamc@12:       | L'.CError => kerror
adamc@12:       | L'.CUnif (k, _, _) => k
adamc@12: 
adamc@12: fun unifyRecordCons env (c1, c2) =
adamc@12:     let
adamc@12:         val k1 = kindof env c1
adamc@12:         val k2 = kindof env c2
adamc@12:     in
adamc@12:         unifyKinds k1 k2;
adamc@12:         unifySummaries env (k1, recordSummary env c1, recordSummary env c2)
adamc@12:     end
adamc@12: 
adamc@12: and recordSummary env c : record_summary =
adamc@12:     case hnormCon env c of
adamc@12:         (L'.CRecord (_, xcs), _) => {fields = xcs, unifs = [], others = []}
adamc@12:       | (L'.CConcat (c1, c2), _) =>
adamc@12:         let
adamc@12:             val s1 = recordSummary env c1
adamc@12:             val s2 = recordSummary env c2
adamc@12:         in
adamc@12:             {fields = #fields s1 @ #fields s2,
adamc@12:              unifs = #unifs s1 @ #unifs s2,
adamc@12:              others = #others s1 @ #others s2}
adamc@12:         end
adamc@12:       | (L'.CUnif (_, _, ref (SOME c)), _) => recordSummary env c
adamc@12:       | c' as (L'.CUnif (_, _, r), _) => {fields = [], unifs = [(c', r)], others = []}
adamc@12:       | c' => {fields = [], unifs = [], others = [c']}
adamc@12: 
adamc@12: and consEq env (c1, c2) =
adamc@12:     (unifyCons env c1 c2;
adamc@12:      true)
adamc@12:     handle CUnify _ => false
adamc@12: 
adamc@12: and unifySummaries env (k, s1 : record_summary, s2 : record_summary) =
adamc@12:     let
adamc@14:         (*val () = eprefaces "Summaries" [("#1", p_summary env s1),
adamc@14:                                           ("#2", p_summary env s2)]*)
adamc@12: 
adamc@12:         fun eatMatching p (ls1, ls2) =
adamc@12:             let
adamc@12:                 fun em (ls1, ls2, passed1) =
adamc@12:                     case ls1 of
adamc@12:                         [] => (rev passed1, ls2)
adamc@12:                       | h1 :: t1 =>
adamc@12:                         let
adamc@12:                             fun search (ls2', passed2) =
adamc@12:                                 case ls2' of
adamc@12:                                     [] => em (t1, ls2, h1 :: passed1)
adamc@12:                                   | h2 :: t2 =>
adamc@12:                                     if p (h1, h2) then
adamc@12:                                         em (t1, List.revAppend (passed2, t2), passed1)
adamc@12:                                     else
adamc@12:                                         search (t2, h2 :: passed2)
adamc@12:                         in
adamc@12:                             search (ls2, [])
adamc@12:                         end
adamc@12:             in
adamc@12:                 em (ls1, ls2, [])
adamc@12:             end
adamc@12: 
adamc@12:         val (fs1, fs2) = eatMatching (fn ((x1, c1), (x2, c2)) =>
adamc@12:                                          if consEq env (x1, x2) then
adamc@12:                                              (unifyCons env c1 c2;
adamc@12:                                               true)
adamc@12:                                          else
adamc@12:                                              false) (#fields s1, #fields s2)
adamc@14:         (*val () = eprefaces "Summaries2" [("#1", p_summary env {fields = fs1, unifs = #unifs s1, others = #others s1}),
adamc@14:                                            ("#2", p_summary env {fields = fs2, unifs = #unifs s2, others = #others s2})]*)
adamc@12:         val (unifs1, unifs2) = eatMatching (fn ((_, r1), (_, r2)) => r1 = r2) (#unifs s1, #unifs s2)
adamc@12:         val (others1, others2) = eatMatching (consEq env) (#others s1, #others s2)
adamc@12: 
adamc@12:         fun unifFields (fs, others, unifs) =
adamc@12:             case (fs, others, unifs) of
adamc@12:                 ([], [], _) => ([], [], unifs)
adamc@12:               | (_, _, []) => (fs, others, [])
adamc@12:               | (_, _, (_, r) :: rest) =>
adamc@12:                 let
adamc@12:                     val r' = ref NONE
adamc@12:                     val cr' = (L'.CUnif (k, "recd", r'), dummy)
adamc@12: 
adamc@12:                     val prefix = case (fs, others) of
adamc@12:                                      ([], other :: others) =>
adamc@12:                                      List.foldl (fn (other, c) =>
adamc@12:                                                     (L'.CConcat (c, other), dummy))
adamc@12:                                                 other others
adamc@12:                                    | (fs, []) =>
adamc@12:                                      (L'.CRecord (k, fs), dummy)
adamc@12:                                    | (fs, others) =>
adamc@12:                                      List.foldl (fn (other, c) =>
adamc@12:                                                     (L'.CConcat (c, other), dummy))
adamc@12:                                                 (L'.CRecord (k, fs), dummy) others
adamc@12:                 in
adamc@12:                     r := SOME (L'.CConcat (prefix, cr'), dummy);
adamc@12:                     ([], [], (cr', r') :: rest)
adamc@12:                 end
adamc@12: 
adamc@12:         val (fs1, others1, unifs2) = unifFields (fs1, others1, unifs2)
adamc@12:         val (fs2, others2, unifs1) = unifFields (fs2, others2, unifs1)
adamc@12: 
adamc@12:         val clear1 = case (fs1, others1) of
adamc@12:                          ([], []) => true
adamc@12:                        | _ => false
adamc@12:         val clear2 = case (fs2, others2) of
adamc@12:                          ([], []) => true
adamc@12:                        | _ => false
adamc@12:         val empty = (L'.CRecord (k, []), dummy)
adamc@12:         fun pairOffUnifs (unifs1, unifs2) =
adamc@12:             case (unifs1, unifs2) of
adamc@12:                 ([], _) =>
adamc@12:                 if clear1 then
adamc@12:                     List.app (fn (_, r) => r := SOME empty) unifs2
adamc@12:                 else
adamc@12:                     raise CUnify' CRecordFailure
adamc@12:               | (_, []) =>
adamc@12:                 if clear2 then
adamc@12:                     List.app (fn (_, r) => r := SOME empty) unifs1
adamc@12:                 else
adamc@12:                     raise CUnify' CRecordFailure
adamc@12:               | ((c1, _) :: rest1, (_, r2) :: rest2) =>
adamc@12:                 (r2 := SOME c1;
adamc@12:                  pairOffUnifs (rest1, rest2))
adamc@12:     in
adamc@12:         pairOffUnifs (unifs1, unifs2)
adamc@12:     end
adamc@12: 
adamc@12: and hnormCon env (cAll as (c, _)) =
adamc@11:     case c of
adamc@11:         L'.CUnif (_, _, ref (SOME c)) => hnormCon env c
adamc@11: 
adamc@11:       | L'.CNamed xn =>
adamc@11:         (case E.lookupCNamed env xn of
adamc@11:              (_, _, SOME c') => hnormCon env c'
adamc@11:            | _ => cAll)
adamc@11: 
adamc@12:       | L'.CApp (c1, c2) =>
adamc@12:         (case hnormCon env c1 of
adamc@12:              (L'.CAbs (_, _, cb), _) =>
adamc@12:              ((hnormCon env (subConInCon (0, c2) cb))
adamc@12:               handle SynUnif => cAll)
adamc@12:            | _ => cAll)
adamc@12: 
adamc@12:       | L'.CConcat (c1, c2) =>
adamc@12:         (case (hnormCon env c1, hnormCon env c2) of
adamc@12:              ((L'.CRecord (k, xcs1), loc), (L'.CRecord (_, xcs2), _)) =>
adamc@12:              (L'.CRecord (k, xcs1 @ xcs2), loc)
adamc@12:            | _ => cAll)
adamc@12: 
adamc@11:       | _ => cAll
adamc@11: 
adamc@12: and unifyCons' env c1 c2 =
adamc@11:     unifyCons'' env (hnormCon env c1) (hnormCon env c2)
adamc@11:     
adamc@11: and unifyCons'' env (c1All as (c1, _)) (c2All as (c2, _)) =
adamc@10:     let
adamc@10:         fun err f = raise CUnify' (f (c1All, c2All))
adamc@12: 
adamc@12:         fun isRecord () = unifyRecordCons env (c1All, c2All)
adamc@10:     in
adamc@10:         case (c1, c2) of
adamc@10:             (L'.TFun (d1, r1), L'.TFun (d2, r2)) =>
adamc@10:             (unifyCons' env d1 d2;
adamc@10:              unifyCons' env r1 r2)
adamc@10:           | (L'.TCFun (expl1, x1, d1, r1), L'.TCFun (expl2, _, d2, r2)) =>
adamc@10:             if expl1 <> expl2 then
adamc@10:                 err CExplicitness
adamc@10:             else
adamc@10:                 (unifyKinds d1 d2;
adamc@10:                  unifyCons' (E.pushCRel env x1 d1) r1 r2)
adamc@10:           | (L'.TRecord r1, L'.TRecord r2) => unifyCons' env r1 r2
adamc@10: 
adamc@10:           | (L'.CRel n1, L'.CRel n2) =>
adamc@10:             if n1 = n2 then
adamc@10:                 ()
adamc@10:             else
adamc@10:                 err CIncompatible
adamc@10:           | (L'.CNamed n1, L'.CNamed n2) =>
adamc@10:             if n1 = n2 then
adamc@10:                 ()
adamc@10:             else
adamc@10:                 err CIncompatible
adamc@10: 
adamc@10:           | (L'.CApp (d1, r1), L'.CApp (d2, r2)) =>
adamc@10:             (unifyCons' env d1 d2;
adamc@10:              unifyCons' env r1 r2)
adamc@10:           | (L'.CAbs (x1, k1, c1), L'.CAbs (_, k2, c2)) =>
adamc@10:             (unifyKinds k1 k2;
adamc@10:              unifyCons' (E.pushCRel env x1 k1) c1 c2)
adamc@10: 
adamc@10:           | (L'.CName n1, L'.CName n2) =>
adamc@10:             if n1 = n2 then
adamc@10:                 ()
adamc@10:             else
adamc@10:                 err CIncompatible
adamc@10: 
adamc@10:           | (L'.CError, _) => ()
adamc@10:           | (_, L'.CError) => ()
adamc@10: 
adamc@10:           | (L'.CUnif (_, _, ref (SOME c1All)), _) => unifyCons' env c1All c2All
adamc@10:           | (_, L'.CUnif (_, _, ref (SOME c2All))) => unifyCons' env c1All c2All
adamc@10: 
adamc@10:           | (L'.CUnif (k1, _, r1), L'.CUnif (k2, _, r2)) =>
adamc@10:             if r1 = r2 then
adamc@10:                 ()
adamc@10:             else
adamc@10:                 (unifyKinds k1 k2;
adamc@10:                  r1 := SOME c2All)
adamc@10: 
adamc@10:           | (L'.CUnif (_, _, r), _) =>
adamc@10:             if occursCon r c2All then
adamc@10:                 err COccursCheckFailed
adamc@10:             else
adamc@10:                 r := SOME c2All
adamc@10:           | (_, L'.CUnif (_, _, r)) =>
adamc@10:             if occursCon r c1All then
adamc@10:                 err COccursCheckFailed
adamc@10:             else
adamc@10:                 r := SOME c1All
adamc@10: 
adamc@12:           | (L'.CRecord _, _) => isRecord ()
adamc@12:           | (_, L'.CRecord _) => isRecord ()
adamc@12:           | (L'.CConcat _, _) => isRecord ()
adamc@12:           | (_, L'.CConcat _) => isRecord ()
adamc@12: 
adamc@10:           | _ => err CIncompatible
adamc@10:     end
adamc@10: 
adamc@12: and unifyCons env c1 c2 =
adamc@10:     unifyCons' env c1 c2
adamc@10:     handle CUnify' err => raise CUnify (c1, c2, err)
adamc@10:          | KUnify args => raise CUnify (c1, c2, CKind args)
adamc@10: 
adamc@10: datatype exp_error =
adamc@10:        UnboundExp of ErrorMsg.span * string
adamc@10:      | Unify of L'.exp * L'.con * L'.con * cunify_error
adamc@11:      | Unif of string * L'.con
adamc@11:      | WrongForm of string * L'.exp * L'.con
adamc@10: 
adamc@10: fun expError env err =
adamc@10:     case err of
adamc@10:         UnboundExp (loc, s) =>
adamc@10:         ErrorMsg.errorAt loc ("Unbound expression variable " ^ s)
adamc@10:       | Unify (e, c1, c2, uerr) =>
adamc@10:         (ErrorMsg.errorAt (#2 e) "Unification failure";
adamc@10:          eprefaces' [("Expression", p_exp env e),
adamc@10:                      ("Have con", p_con env c1),
adamc@10:                      ("Need con", p_con env c2)];
adamc@10:          cunifyError env uerr)
adamc@11:       | Unif (action, c) =>
adamc@11:         (ErrorMsg.errorAt (#2 c) ("Unification variable blocks " ^ action);
adamc@11:          eprefaces' [("Con", p_con env c)])
adamc@11:       | WrongForm (variety, e, t) =>
adamc@11:         (ErrorMsg.errorAt (#2 e) ("Expression is not a " ^ variety);
adamc@11:          eprefaces' [("Expression", p_exp env e),
adamc@11:                      ("Type", p_con env t)])
adamc@10: 
adamc@10: fun checkCon env e c1 c2 =
adamc@10:     unifyCons env c1 c2
adamc@10:     handle CUnify (c1, c2, err) =>
adamc@10:            expError env (Unify (e, c1, c2, err))
adamc@10: 
adamc@14: fun primType env p =
adamc@14:     let
adamc@14:         val s = case p of
adamc@14:                     P.Int _ => "int"
adamc@14:                   | P.Float _ => "float"
adamc@14:                   | P.String _ => "string"
adamc@14:     in
adamc@14:         case E.lookupC env s of
adamc@14:             E.NotBound => raise Fail ("Primitive type " ^ s ^ " unbound")
adamc@14:           | E.Rel _ => raise Fail ("Primitive type " ^ s ^ " bound as relative")
adamc@14:           | E.Named (n, (L'.KType, _)) => L'.CNamed n
adamc@14:           | E.Named _ => raise Fail ("Primitive type " ^ s ^ " bound at non-Type kind")
adamc@14:     end
adamc@14: 
adamc@15: fun typeof env (e, loc) =
adamc@15:     case e of
adamc@15:         L'.EPrim p => (primType env p, loc)
adamc@15:       | L'.ERel n => #2 (E.lookupERel env n)
adamc@15:       | L'.ENamed n => #2 (E.lookupENamed env n)
adamc@15:       | L'.EApp (e1, _) =>
adamc@15:         (case #1 (typeof env e1) of
adamc@15:              L'.TFun (_, c) => c
adamc@15:            | _ => raise Fail "typeof: Bad EApp")
adamc@15:       | L'.EAbs (x, t, e1) => (L'.TFun (t, typeof (E.pushERel env x t) e1), loc)
adamc@15:       | L'.ECApp (e1, c) =>
adamc@15:         (case #1 (typeof env e1) of
adamc@15:              L'.TCFun (_, _, _, c1) => subConInCon (0, c) c1
adamc@15:            | _ => raise Fail "typeof: Bad ECApp")
adamc@15:       | L'.ECAbs (expl, x, k, e1) => (L'.TCFun (expl, x, k, typeof (E.pushCRel env x k) e1), loc)
adamc@15: 
adamc@15:       | L'.ERecord xes => (L'.TRecord (L'.CRecord (ktype, map (fn (x, e) => (x, typeof env e)) xes), loc), loc)
adamc@15:       | L'.EField (_, _, {field, ...}) => field
adamc@15: 
adamc@15:       | L'.EError => cerror
adamc@15: 
adamc@15: fun elabHead env (e as (_, loc)) t =
adamc@15:     let
adamc@15:         fun unravel (t, e) =
adamc@15:             case hnormCon env t of
adamc@15:                 (L'.TCFun (L'.Implicit, x, k, t'), _) =>
adamc@15:                 let
adamc@15:                     val u = cunif k
adamc@15:                 in
adamc@15:                     unravel (subConInCon (0, u) t',
adamc@15:                              (L'.ECApp (e, u), loc))
adamc@15:                 end
adamc@15:               | _ => (e, t)
adamc@15:     in
adamc@15:         unravel (t, e)
adamc@15:     end
adamc@15: 
adamc@10: fun elabExp env (e, loc) =
adamc@10:     case e of
adamc@10:         L.EAnnot (e, t) =>
adamc@10:         let
adamc@10:             val (e', et) = elabExp env e
adamc@10:             val (t', _) = elabCon env t
adamc@10:         in
adamc@10:             checkCon env e' et t';
adamc@10:             (e', t')
adamc@10:         end
adamc@10: 
adamc@14:       | L.EPrim p => ((L'.EPrim p, loc), (primType env p, loc))
adamc@10:       | L.EVar s =>
adamc@10:         (case E.lookupE env s of
adamc@10:              E.NotBound =>
adamc@10:              (expError env (UnboundExp (loc, s));
adamc@10:               (eerror, cerror))
adamc@10:            | E.Rel (n, t) => ((L'.ERel n, loc), t)
adamc@10:            | E.Named (n, t) => ((L'.ENamed n, loc), t))
adamc@10:       | L.EApp (e1, e2) =>
adamc@10:         let
adamc@10:             val (e1', t1) = elabExp env e1
adamc@15:             val (e1', t1) = elabHead env e1' t1
adamc@10:             val (e2', t2) = elabExp env e2
adamc@10: 
adamc@10:             val dom = cunif ktype
adamc@10:             val ran = cunif ktype
adamc@10:             val t = (L'.TFun (dom, ran), dummy)
adamc@10:         in
adamc@10:             checkCon env e1' t1 t;
adamc@10:             checkCon env e2' t2 dom;
adamc@10:             ((L'.EApp (e1', e2'), loc), ran)
adamc@10:         end
adamc@10:       | L.EAbs (x, to, e) =>
adamc@10:         let
adamc@10:             val t' = case to of
adamc@10:                          NONE => cunif ktype
adamc@10:                        | SOME t =>
adamc@10:                          let
adamc@10:                              val (t', tk) = elabCon env t
adamc@10:                          in
adamc@10:                              checkKind env t' tk ktype;
adamc@10:                              t'
adamc@10:                          end
adamc@10:             val (e', et) = elabExp (E.pushERel env x t') e
adamc@10:         in
adamc@10:             ((L'.EAbs (x, t', e'), loc),
adamc@10:              (L'.TFun (t', et), loc))
adamc@10:         end
adamc@10:       | L.ECApp (e, c) =>
adamc@10:         let
adamc@10:             val (e', et) = elabExp env e
adamc@15:             val (e', et) = elabHead env e' et
adamc@10:             val (c', ck) = elabCon env c
adamc@10:         in
adamc@11:             case #1 (hnormCon env et) of
adamc@11:                 L'.CError => (eerror, cerror)
adamc@11:               | L'.TCFun (_, _, k, eb) =>
adamc@11:                 let
adamc@11:                     val () = checkKind env c' ck k
adamc@11:                     val eb' = subConInCon (0, c') eb
adamc@11:                               handle SynUnif => (expError env (Unif ("substitution", eb));
adamc@11:                                                  cerror)
adamc@11:                 in
adamc@11:                     ((L'.ECApp (e', c'), loc), eb')
adamc@11:                 end
adamc@11: 
adamc@11:               | L'.CUnif _ =>
adamc@11:                 (expError env (Unif ("application", et));
adamc@11:                  (eerror, cerror))
adamc@11: 
adamc@11:               | _ =>
adamc@11:                 (expError env (WrongForm ("constructor function", e', et));
adamc@11:                  (eerror, cerror))
adamc@10:         end
adamc@11:       | L.ECAbs (expl, x, k, e) =>
adamc@11:         let
adamc@11:             val expl' = elabExplicitness expl
adamc@11:             val k' = elabKind k
adamc@11:             val (e', et) = elabExp (E.pushCRel env x k') e
adamc@11:         in
adamc@11:             ((L'.ECAbs (expl', x, k', e'), loc),
adamc@11:              (L'.TCFun (expl', x, k', et), loc))
adamc@11:         end
adamc@6: 
adamc@12:       | L.ERecord xes =>
adamc@12:         let
adamc@12:             val xes' = map (fn (x, e) =>
adamc@12:                                let
adamc@12:                                    val (x', xk) = elabCon env x
adamc@12:                                    val (e', et) = elabExp env e
adamc@12:                                in
adamc@12:                                    checkKind env x' xk kname;
adamc@12:                                    (x', e', et)
adamc@12:                                end) xes
adamc@12:         in
adamc@12:             ((L'.ERecord (map (fn (x', e', _) => (x', e')) xes'), loc),
adamc@12:              (L'.TRecord (L'.CRecord (ktype, map (fn (x', _, et) => (x', et)) xes'), loc), loc))
adamc@12:         end
adamc@12: 
adamc@12:       | L.EField (e, c) =>
adamc@12:         let
adamc@12:             val (e', et) = elabExp env e
adamc@12:             val (c', ck) = elabCon env c
adamc@12: 
adamc@12:             val ft = cunif ktype
adamc@12:             val rest = cunif ktype_record
adamc@12:         in
adamc@12:             checkKind env c' ck kname;
adamc@12:             checkCon env e' et (L'.TRecord (L'.CConcat ((L'.CRecord (ktype, [(c', ft)]), loc), rest), loc), loc);
adamc@12:             ((L'.EField (e', c', {field = ft, rest = rest}), loc), ft)
adamc@12:         end
adamc@12:             
adamc@12: 
adamc@6: datatype decl_error =
adamc@6:          KunifsRemainKind of ErrorMsg.span * L'.kind
adamc@6:        | KunifsRemainCon of ErrorMsg.span * L'.con
adamc@10:        | KunifsRemainExp of ErrorMsg.span * L'.exp
adamc@10:        | CunifsRemainCon of ErrorMsg.span * L'.con
adamc@10:        | CunifsRemainExp of ErrorMsg.span * L'.exp
adamc@6: 
adamc@6: fun declError env err =
adamc@6:     case err of
adamc@6:         KunifsRemainKind (loc, k) =>
adamc@6:         (ErrorMsg.errorAt loc "Some kind unification variables are undetermined in kind";
adamc@6:          eprefaces' [("Kind", p_kind k)])
adamc@6:       | KunifsRemainCon (loc, c) =>
adamc@6:         (ErrorMsg.errorAt loc "Some kind unification variables are undetermined in constructor";
adamc@6:          eprefaces' [("Constructor", p_con env c)])
adamc@10:       | KunifsRemainExp (loc, e) =>
adamc@10:         (ErrorMsg.errorAt loc "Some kind unification variables are undetermined in expression";
adamc@10:          eprefaces' [("Expression", p_exp env e)])
adamc@10:       | CunifsRemainCon (loc, c) =>
adamc@10:         (ErrorMsg.errorAt loc "Some constructor unification variables are undetermined in constructor";
adamc@10:          eprefaces' [("Constructor", p_con env c)])
adamc@10:       | CunifsRemainExp (loc, e) =>
adamc@10:         (ErrorMsg.errorAt loc "Some constructor unification variables are undetermined in expression";
adamc@10:          eprefaces' [("Expression", p_exp env e)])
adamc@6: 
adamc@3: fun elabDecl env (d, loc) =
adamc@5:     (resetKunif ();
adamc@12:      resetCunif ();
adamc@5:      case d of
adamc@5:          L.DCon (x, ko, c) =>
adamc@5:          let
adamc@5:              val k' = case ko of
adamc@5:                           NONE => kunif ()
adamc@5:                         | SOME k => elabKind k
adamc@3: 
adamc@5:              val (c', ck) = elabCon env c
adamc@11:              val (env', n) = E.pushCNamed env x k' (SOME c')
adamc@5:          in
adamc@5:              checkKind env c' ck k';
adamc@6: 
adamc@15:              if ErrorMsg.anyErrors () then
adamc@15:                  ()
adamc@15:              else (
adamc@15:                  if kunifsInKind k' then
adamc@15:                      declError env (KunifsRemainKind (loc, k'))
adamc@15:                  else
adamc@15:                      ();
adamc@6: 
adamc@15:                  if kunifsInCon c' then
adamc@15:                      declError env (KunifsRemainCon (loc, c'))
adamc@15:                  else
adamc@15:                      ()
adamc@15:                  );
adamc@6: 
adamc@5:              (env',
adamc@5:               (L'.DCon (x, n, k', c'), loc))
adamc@10:          end
adamc@10:        | L.DVal (x, co, e) =>
adamc@10:          let
adamc@10:              val (c', ck) = case co of
adamc@10:                                 NONE => (cunif ktype, ktype)
adamc@10:                               | SOME c => elabCon env c
adamc@10: 
adamc@10:              val (e', et) = elabExp env e
adamc@10:              val (env', n) = E.pushENamed env x c'
adamc@10:          in
adamc@10:              checkCon env e' et c';
adamc@10: 
adamc@15:              if ErrorMsg.anyErrors () then
adamc@15:                  ()
adamc@15:              else (
adamc@15:                  if kunifsInCon c' then
adamc@15:                      declError env (KunifsRemainCon (loc, c'))
adamc@15:                  else
adamc@15:                      ();
adamc@10: 
adamc@15:                  if cunifsInCon c' then
adamc@15:                      declError env (CunifsRemainCon (loc, c'))
adamc@15:                  else
adamc@15:                      ();
adamc@10: 
adamc@15:                  if kunifsInExp e' then
adamc@15:                      declError env (KunifsRemainExp (loc, e'))
adamc@15:                  else
adamc@15:                      ();
adamc@10: 
adamc@15:                  if cunifsInExp e' then
adamc@15:                      declError env (CunifsRemainExp (loc, e'))
adamc@15:                  else
adamc@15:                      ());
adamc@10: 
adamc@10:              (env',
adamc@10:               (L'.DVal (x, n, c', e'), loc))
adamc@5:          end)
adamc@3: 
adamc@5: fun elabFile env ds =
adamc@5:     ListUtil.mapfoldl (fn (d, env) => elabDecl env d) env ds
adamc@2: 
adamc@2: end