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@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 elabKind (k, loc) =
adamc@2:     case k of
adamc@2:         L.KType => (L'.KType, loc)
adamc@2:       | L.KArrow (k1, k2) => (L'.KArrow (elabKind k1, elabKind k2), loc)
adamc@2:       | L.KName => (L'.KName, loc)
adamc@2:       | L.KRecord k => (L'.KRecord (elabKind k), loc)
adamc@2: 
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@3: 
adamc@3: val cerror = (L'.CError, dummy)
adamc@3: val kerror = (L'.KError, 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@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@3:              E.CNotBound =>
adamc@5:              (conError env (UnboundCon (loc, s));
adamc@3:               (cerror, kerror))
adamc@3:            | E.CRel (n, k) =>
adamc@3:              ((L'.CRel n, loc), k)
adamc@3:            | E.CNamed (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@6: fun kunifsRemain k =
adamc@6:     case k of
adamc@6:         L'.KUnif (_, ref NONE) => true
adamc@6:       | _ => 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@6: 
adamc@6: datatype decl_error =
adamc@6:          KunifsRemainKind of ErrorMsg.span * L'.kind
adamc@6:        | KunifsRemainCon of ErrorMsg.span * L'.con
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@6: 
adamc@3: fun elabDecl env (d, loc) =
adamc@5:     (resetKunif ();
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@5:              val (env', n) = E.pushCNamed env x k'
adamc@5:          in
adamc@5:              checkKind env c' ck k';
adamc@6: 
adamc@6:              if kunifsInKind k' then
adamc@6:                  declError env (KunifsRemainKind (loc, k'))
adamc@6:              else
adamc@6:                  ();
adamc@6: 
adamc@6:              if kunifsInCon c' then
adamc@6:                  declError env (KunifsRemainCon (loc, c'))
adamc@6:              else
adamc@6:                  ();
adamc@6: 
adamc@5:              (env',
adamc@5:               (L'.DCon (x, n, k', c'), 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