adamc@81: (* Copyright (c) 2008, Adam Chlipala
adamc@81:  * All rights reserved.
adamc@81:  *
adamc@81:  * Redistribution and use in source and binary forms, with or without
adamc@81:  * modification, are permitted provided that the following conditions are met:
adamc@81:  *
adamc@81:  * - Redistributions of source code must retain the above copyright notice,
adamc@81:  *   this list of conditions and the following disclaimer.
adamc@81:  * - Redistributions in binary form must reproduce the above copyright notice,
adamc@81:  *   this list of conditions and the following disclaimer in the documentation
adamc@81:  *   and/or other materials provided with the distribution.
adamc@81:  * - The names of contributors may not be used to endorse or promote products
adamc@81:  *   derived from this software without specific prior written permission.
adamc@81:  *
adamc@81:  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
adamc@81:  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
adamc@81:  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
adamc@81:  * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
adamc@81:  * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 
adamc@81:  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
adamc@81:  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
adamc@81:  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
adamc@81:  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
adamc@81:  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
adamc@81:  * POSSIBILITY OF SUCH DAMAGE.
adamc@81:  *)
adamc@81: 
adamc@81: structure ElabOps :> ELAB_OPS = struct
adamc@81: 
adamc@81: open Elab
adamc@81: 
adamc@81: structure E = ElabEnv
adamc@81: structure U = ElabUtil
adamc@81: 
adamc@623: fun liftKindInKind' by =
adamc@623:     U.Kind.mapB {kind = fn bound => fn k =>
adamc@623:                                        case k of
adamc@623:                                          KRel xn =>
adamc@623:                                          if xn < bound then
adamc@623:                                              k
adamc@623:                                          else
adamc@623:                                              KRel (xn + by)
adamc@623:                                        | _ => k,
adamc@623:                 bind = fn (bound, _) => bound + 1}
adamc@623: 
adamc@623: fun subKindInKind' rep =
adamc@623:     U.Kind.mapB {kind = fn (by, xn) => fn k =>
adamc@623:                                           case k of
adamc@623:                                               KRel xn' =>
adamc@623:                                               (case Int.compare (xn', xn) of
adamc@623:                                                    EQUAL => #1 (liftKindInKind' by 0 rep)
adamc@623:                                                  | GREATER => KRel (xn' - 1)
adamc@623:                                                  | LESS => k)
adamc@623:                                             | _ => k,
adamc@623:                  bind = fn ((by, xn), _) => (by+1, xn+1)}
adamc@623: 
adamc@623: val liftKindInKind = liftKindInKind' 1
adamc@623: 
adamc@623: fun subKindInKind (xn, rep) = subKindInKind' rep (0, xn)
adamc@623: 
adamc@623: fun liftKindInCon by =
adamc@623:     U.Con.mapB {kind = fn bound => fn k =>
adamc@623:                                       case k of
adamc@623:                                           KRel xn =>
adamc@623:                                           if xn < bound then
adamc@623:                                               k
adamc@623:                                           else
adamc@623:                                               KRel (xn + by)
adamc@623:                                         | _ => k,
adamc@623:                 con = fn _ => fn c => c,
adamc@623:                 bind = fn (bound, U.Con.RelK _) => bound + 1
adamc@623:                         | (bound, _) => bound}
adamc@623: 
adamc@623: fun subKindInCon' rep =
adamc@623:     U.Con.mapB {kind = fn (by, xn) => fn k =>
adamc@623:                                          case k of
adamc@623:                                              KRel xn' =>
adamc@623:                                              (case Int.compare (xn', xn) of
adamc@623:                                                   EQUAL => #1 (liftKindInKind' by 0 rep)
adamc@623:                                                 | GREATER => KRel (xn' - 1)
adamc@623:                                                 | LESS => k)
adamc@623:                                            | _ => k,
adamc@623:                 con = fn _ => fn c => c,
adamc@623:                 bind = fn ((by, xn), U.Con.RelK _) => (by+1, xn+1)
adamc@623:                         | (st, _) => st}
adamc@623: 
adamc@623: val liftKindInCon = liftKindInCon 1
adamc@623: 
adamc@623: fun subKindInCon (xn, rep) = subKindInCon' rep (0, xn)
adamc@623: 
adamc@516: fun liftConInCon by =
adamc@623:     U.Con.mapB {kind = fn _ => fn k => k,
adamc@516:                 con = fn bound => fn c =>
adamc@516:                                      case c of
adamc@516:                                          CRel xn =>
adamc@516:                                          if xn < bound then
adamc@516:                                              c
adamc@516:                                          else
adamc@516:                                              CRel (xn + by)
adam@1303:                                        | CUnif (nl, loc, k, s, r) => CUnif (nl+by, loc, k, s, r)
adamc@516:                                        | _ => c,
adamc@623:                 bind = fn (bound, U.Con.RelC _) => bound + 1
adamc@516:                         | (bound, _) => bound}
adamc@81: 
adam@1303: exception SubUnif
adam@1303: 
adamc@516: fun subConInCon' rep =
adamc@623:     U.Con.mapB {kind = fn _ => fn k => k,
adamc@516:                 con = fn (by, xn) => fn c =>
adamc@516:                                         case c of
adamc@516:                                             CRel xn' =>
adamc@516:                                             (case Int.compare (xn', xn) of
adamc@516:                                                  EQUAL => #1 (liftConInCon by 0 rep)
adamc@516:                                                | GREATER => CRel (xn' - 1)
adamc@516:                                                | LESS => c)
adam@1303:                                           | CUnif (0, _, _, _, _) => raise SubUnif
adam@1303:                                           | CUnif (n, loc, k, s, r) => CUnif (n-1, loc, k, s, r)
adamc@516:                                           | _ => c,
adamc@623:                 bind = fn ((by, xn), U.Con.RelC _) => (by+1, xn+1)
adamc@81:                         | (ctx, _) => ctx}
adamc@81: 
adamc@516: val liftConInCon = liftConInCon 1
adamc@516: 
adamc@516: fun subConInCon (xn, rep) = subConInCon' rep (0, xn)
adamc@516: 
adamc@81: fun subStrInSgn (m1, m2) =
adamc@81:     U.Sgn.map {kind = fn k => k,
adamc@81:                con = fn c as CModProj (m1', ms, x) =>
adamc@81:                         if m1 = m1' then
adamc@81:                             CModProj (m2, ms, x)
adamc@81:                         else
adamc@81:                             c
adamc@81:                       | c => c,
adamc@81:                sgn_item = fn sgi => sgi,
adamc@81:                sgn = fn sgn => sgn}
adamc@81: 
adamc@905: val occurs =
adamc@905:     U.Con.existsB {kind = fn _ => false,
adamc@905:                    con = fn (n, c) =>
adamc@905:                             case c of
adamc@905:                                 CRel n' => n' = n
adamc@905:                               | _ => false,
adamc@905:                    bind = fn (n, b) =>
adamc@905:                              case b of
adamc@905:                                  U.Con.RelC _ => n + 1
adamc@905:                                | _ => n}
adamc@905:                   0
adamc@905: 
adamc@1034: val identity = ref 0
adamc@1034: val distribute = ref 0
adamc@1034: val fuse = ref 0
adamc@1034: 
adamc@1034: fun reset () = (identity := 0;
adamc@1034:                 distribute := 0;
adamc@1034:                 fuse := 0)
adamc@81: 
adamc@81: fun hnormCon env (cAll as (c, loc)) =
adamc@81:     case c of
adam@1591:         CUnif (nl, _, _, _, ref (SOME c)) => (#1 (hnormCon env (E.mliftConInCon nl c)), loc)
adamc@81: 
adamc@81:       | CNamed xn =>
adamc@81:         (case E.lookupCNamed env xn of
adamc@81:              (_, _, SOME c') => hnormCon env c'
adamc@81:            | _ => cAll)
adamc@81: 
adamc@81:       | CModProj (n, ms, x) =>
adamc@81:         let
adamc@81:             val (_, sgn) = E.lookupStrNamed env n
adamc@81:             val (str, sgn) = foldl (fn (m, (str, sgn)) =>
adamc@81:                                        case E.projectStr env {sgn = sgn, str = str, field = m} of
adamc@81:                                            NONE => raise Fail "hnormCon: Unknown substructure"
adamc@81:                                          | SOME sgn => ((StrProj (str, m), loc), sgn))
adamc@81:                              ((StrVar n, loc), sgn) ms
adamc@81:         in
adamc@81:             case E.projectCon env {sgn = sgn, str = str, field = x} of
adamc@81:                 NONE => raise Fail "kindof: Unknown con in structure"
adamc@81:               | SOME (_, NONE) => cAll
adamc@81:               | SOME (_, SOME c) => hnormCon env c
adamc@81:         end
adamc@81: 
adamc@905:       (* Eta reduction *)
adamc@905:       | CAbs (x, k, b) =>
adamc@905:         (case #1 (hnormCon (E.pushCRel env x k) b) of
adamc@905:              CApp (f, (CRel 0, _)) =>
adamc@905:              if occurs f then
adamc@905:                  cAll
adamc@905:              else
adamc@905:                  hnormCon env (subConInCon (0, (CUnit, loc)) f)
adamc@905:            | _ => cAll)
adamc@905: 
adamc@81:       | CApp (c1, c2) =>
adamc@81:         (case #1 (hnormCon env c1) of
adamc@81:              CAbs (x, k, cb) =>
adamc@81:              let
adamc@81:                  val sc = (hnormCon env (subConInCon (0, c2) cb))
adamc@81:                      handle SynUnif => cAll
adamc@81:                  (*val env' = E.pushCRel env x k*)
adamc@81:              in
adamc@328:                  (*Print.eprefaces "Subst" [("x", Print.PD.string x),
adamc@328:                                           ("cb", ElabPrint.p_con env' cb),
adamc@328:                                           ("c2", ElabPrint.p_con env c2),
adamc@328:                                           ("sc", ElabPrint.p_con env sc)];*)
adamc@81:                  sc
adamc@81:              end
adamc@621:            | c1' as CApp (c', f) =>
adamc@326:              let
adamc@326:                  fun default () = (CApp ((c1', loc), hnormCon env c2), loc)
adamc@326:              in
adamc@326:                  case #1 (hnormCon env c') of
adamc@621:                      CMap (ks as (k1, k2)) =>
adamc@621:                      (case #1 (hnormCon env c2) of
adamc@621:                           CRecord (_, []) => (CRecord (k2, []), loc)
adamc@621:                         | CRecord (_, (x, c) :: rest) =>
adamc@621:                           hnormCon env
adamc@621:                                    (CConcat ((CRecord (k2, [(x, (CApp (f, c), loc))]), loc),
adamc@621:                                              (CApp (c1, (CRecord (k2, rest), loc)), loc)), loc)
adamc@621:                         | CConcat ((CRecord (k, (x, c) :: rest), _), rest') =>
adamc@621:                           let
adamc@621:                               val rest'' = (CConcat ((CRecord (k, rest), loc), rest'), loc)
adamc@621:                           in
adamc@621:                               hnormCon env
adamc@621:                                        (CConcat ((CRecord (k2, [(x, (CApp (f, c), loc))]), loc),
adamc@621:                                                  (CApp (c1, rest''), loc)), loc)
adamc@621:                           end
adamc@621:                         | _ =>
adamc@621:                           let
adamc@621:                               fun unconstraint c =
adamc@621:                                   case hnormCon env c of
adamc@628:                                       (TDisjoint (_, _, c), _) => unconstraint c
adamc@621:                                     | c => c
adamc@81: 
adamc@1034:                               fun inc r = r := !r + 1
adamc@1034: 
adamc@621:                               fun tryDistributivity () =
adamc@621:                                   case hnormCon env c2 of
adamc@621:                                       (CConcat (c1, c2'), _) =>
adamc@621:                                       let
adamc@621:                                           val c = (CMap ks, loc)
adamc@621:                                           val c = (CApp (c, f), loc)
adamc@621:                                                   
adamc@621:                                           val c1 = (CApp (c, c1), loc)
adamc@621:                                           val c2 = (CApp (c, c2'), loc)
adamc@621:                                           val c = (CConcat (c1, c2), loc)
adamc@621:                                       in
adamc@1034:                                           inc distribute;
adamc@621:                                           hnormCon env c
adamc@621:                                       end
adamc@621:                                     | _ => default ()
adamc@329: 
adamc@621:                               fun tryFusion () =
adamc@621:                                   case #1 (hnormCon env c2) of
adamc@621:                                       CApp (f', r') =>
adamc@621:                                       (case #1 (hnormCon env f') of
adamc@621:                                            CApp (f', inner_f) =>
adamc@621:                                            (case #1 (hnormCon env f') of
adamc@621:                                                 CMap (dom, _) =>
adamc@621:                                                 let
adamc@990:                                                     val inner_f = liftConInCon 0 inner_f
adamc@990:                                                     val f = liftConInCon 0 f
adamc@990: 
adamc@621:                                                     val f' = (CApp (inner_f, (CRel 0, loc)), loc)
adamc@621:                                                     val f' = (CApp (f, f'), loc)
adamc@621:                                                     val f' = (CAbs ("v", dom, f'), loc)
adamc@329: 
adamc@621:                                                     val c = (CMap (dom, k2), loc)
adamc@621:                                                     val c = (CApp (c, f'), loc)
adamc@621:                                                     val c = (CApp (c, r'), loc)
adamc@621:                                                 in
adamc@1034:                                                     inc fuse;
adamc@621:                                                     hnormCon env c
adamc@621:                                                 end
adamc@621:                                               | _ => tryDistributivity ())
adamc@621:                                          | _ => tryDistributivity ())
adamc@621:                                     | _ => tryDistributivity ()
adamc@339: 
adamc@621:                               fun tryIdentity () =
adamc@621:                                   let
adamc@621:                                       fun cunif () =
adamc@621:                                           let
adamc@621:                                               val r = ref NONE
adamc@621:                                           in
adam@1303:                                               (r, (CUnif (0, loc, (KType, loc), "_", r), loc))
adamc@621:                                           end
adamc@621:                                           
adamc@621:                                       val (vR, v) = cunif ()
adamc@494: 
adamc@621:                                       val c = (CApp (f, v), loc)
adamc@621:                                   in
adamc@621:                                       case unconstraint c of
adam@1303:                                           (CUnif (_, _, _, _, vR'), _) =>
adamc@621:                                           if vR' = vR then
adamc@1034:                                               (inc identity;
adamc@1034:                                                hnormCon env c2)
adamc@621:                                           else
adamc@621:                                               tryFusion ()
adamc@621:                                         | _ => tryFusion ()
adamc@621:                                   end
adamc@621:                           in
adamc@621:                               tryIdentity ()
adamc@621:                           end)
adamc@326:                    | _ => default ()
adamc@326:              end
adamc@326:            | c1' => (CApp ((c1', loc), hnormCon env c2), loc))
adamc@623: 
adamc@623:       | CKApp (c1, k) =>
adamc@623:         (case hnormCon env c1 of
adamc@623:              (CKAbs (_, body), _) => hnormCon env (subKindInCon (0, k) body)
adamc@623:            | _ => cAll)
adamc@621:         
adamc@81:       | CConcat (c1, c2) =>
adamc@81:         (case (hnormCon env c1, hnormCon env c2) of
adamc@81:              ((CRecord (k, xcs1), loc), (CRecord (_, xcs2), _)) =>
adamc@81:              (CRecord (k, xcs1 @ xcs2), loc)
adamc@81:            | ((CRecord (_, []), _), c2') => c2'
adamc@81:            | ((CConcat (c11, c12), loc), c2') =>
adamc@81:              hnormCon env (CConcat (c11, (CConcat (c12, c2'), loc)), loc)
adamc@209:            | (c1', (CRecord (_, []), _)) => c1'
adamc@329:            | (c1', c2') => (CConcat (c1', c2'), loc))
adamc@81: 
adamc@207:       | CProj (c, n) =>
adamc@207:         (case hnormCon env c of
adamc@207:              (CTuple cs, _) => hnormCon env (List.nth (cs, n - 1))
adamc@207:            | _ => cAll)
adamc@207: 
adamc@81:       | _ => cAll
adamc@81: 
adamc@81: end