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|
(* 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 Elaborate :> ELABORATE = struct
structure P = Prim
structure L = Source
structure L' = Elab
structure E = ElabEnv
structure U = ElabUtil
open Print
open ElabPrint
fun elabExplicitness e =
case e of
L.Explicit => L'.Explicit
| L.Implicit => L'.Implicit
fun occursKind r =
U.Kind.exists (fn L'.KUnif (_, r') => r = r'
| _ => false)
datatype kunify_error =
KOccursCheckFailed of L'.kind * L'.kind
| KIncompatible of L'.kind * L'.kind
exception KUnify' of kunify_error
fun kunifyError err =
case err of
KOccursCheckFailed (k1, k2) =>
eprefaces "Kind occurs check failed"
[("Kind 1", p_kind k1),
("Kind 2", p_kind k2)]
| KIncompatible (k1, k2) =>
eprefaces "Incompatible kinds"
[("Kind 1", p_kind k1),
("Kind 2", p_kind k2)]
fun unifyKinds' (k1All as (k1, _)) (k2All as (k2, _)) =
let
fun err f = raise KUnify' (f (k1All, k2All))
in
case (k1, k2) of
(L'.KType, L'.KType) => ()
| (L'.KArrow (d1, r1), L'.KArrow (d2, r2)) =>
(unifyKinds' d1 d2;
unifyKinds' r1 r2)
| (L'.KName, L'.KName) => ()
| (L'.KRecord k1, L'.KRecord k2) => unifyKinds' k1 k2
| (L'.KError, _) => ()
| (_, L'.KError) => ()
| (L'.KUnif (_, ref (SOME k1All)), _) => unifyKinds' k1All k2All
| (_, L'.KUnif (_, ref (SOME k2All))) => unifyKinds' k1All k2All
| (L'.KUnif (_, r1), L'.KUnif (_, r2)) =>
if r1 = r2 then
()
else
r1 := SOME k2All
| (L'.KUnif (_, r), _) =>
if occursKind r k2All then
err KOccursCheckFailed
else
r := SOME k2All
| (_, L'.KUnif (_, r)) =>
if occursKind r k1All then
err KOccursCheckFailed
else
r := SOME k1All
| _ => err KIncompatible
end
exception KUnify of L'.kind * L'.kind * kunify_error
fun unifyKinds k1 k2 =
unifyKinds' k1 k2
handle KUnify' err => raise KUnify (k1, k2, err)
datatype con_error =
UnboundCon of ErrorMsg.span * string
| WrongKind of L'.con * L'.kind * L'.kind * kunify_error
fun conError env err =
case err of
UnboundCon (loc, s) =>
ErrorMsg.errorAt loc ("Unbound constructor variable " ^ s)
| WrongKind (c, k1, k2, kerr) =>
(ErrorMsg.errorAt (#2 c) "Wrong kind";
eprefaces' [("Constructor", p_con env c),
("Have kind", p_kind k1),
("Need kind", p_kind k2)];
kunifyError kerr)
fun checkKind env c k1 k2 =
unifyKinds k1 k2
handle KUnify (k1, k2, err) =>
conError env (WrongKind (c, k1, k2, err))
val dummy = ErrorMsg.dummySpan
val ktype = (L'.KType, dummy)
val kname = (L'.KName, dummy)
val ktype_record = (L'.KRecord ktype, dummy)
val cerror = (L'.CError, dummy)
val kerror = (L'.KError, dummy)
val eerror = (L'.EError, dummy)
val sgnerror = (L'.SgnError, dummy)
val strerror = (L'.StrError, dummy)
local
val count = ref 0
in
fun resetKunif () = count := 0
fun kunif () =
let
val n = !count
val s = if n <= 26 then
str (chr (ord #"A" + n))
else
"U" ^ Int.toString (n - 26)
in
count := n + 1;
(L'.KUnif (s, ref NONE), dummy)
end
end
local
val count = ref 0
in
fun resetCunif () = count := 0
fun cunif k =
let
val n = !count
val s = if n <= 26 then
str (chr (ord #"A" + n))
else
"U" ^ Int.toString (n - 26)
in
count := n + 1;
(L'.CUnif (k, s, ref NONE), dummy)
end
end
fun elabKind (k, loc) =
case k of
L.KType => (L'.KType, loc)
| L.KArrow (k1, k2) => (L'.KArrow (elabKind k1, elabKind k2), loc)
| L.KName => (L'.KName, loc)
| L.KRecord k => (L'.KRecord (elabKind k), loc)
| L.KWild => kunif ()
fun elabCon env (c, loc) =
case c of
L.CAnnot (c, k) =>
let
val k' = elabKind k
val (c', ck) = elabCon env c
in
checkKind env c' ck k';
(c', k')
end
| L.TFun (t1, t2) =>
let
val (t1', k1) = elabCon env t1
val (t2', k2) = elabCon env t2
in
checkKind env t1' k1 ktype;
checkKind env t2' k2 ktype;
((L'.TFun (t1', t2'), loc), ktype)
end
| L.TCFun (e, x, k, t) =>
let
val e' = elabExplicitness e
val k' = elabKind k
val env' = E.pushCRel env x k'
val (t', tk) = elabCon env' t
in
checkKind env t' tk ktype;
((L'.TCFun (e', x, k', t'), loc), ktype)
end
| L.TRecord c =>
let
val (c', ck) = elabCon env c
val k = (L'.KRecord ktype, loc)
in
checkKind env c' ck k;
((L'.TRecord c', loc), ktype)
end
| L.CVar s =>
(case E.lookupC env s of
E.NotBound =>
(conError env (UnboundCon (loc, s));
(cerror, kerror))
| E.Rel (n, k) =>
((L'.CRel n, loc), k)
| E.Named (n, k) =>
((L'.CNamed n, loc), k))
| L.CApp (c1, c2) =>
let
val (c1', k1) = elabCon env c1
val (c2', k2) = elabCon env c2
val dom = kunif ()
val ran = kunif ()
in
checkKind env c1' k1 (L'.KArrow (dom, ran), loc);
checkKind env c2' k2 dom;
((L'.CApp (c1', c2'), loc), ran)
end
| L.CAbs (x, k, t) =>
let
val k' = elabKind k
val env' = E.pushCRel env x k'
val (t', tk) = elabCon env' t
in
((L'.CAbs (x, k', t'), loc),
(L'.KArrow (k', tk), loc))
end
| L.CName s =>
((L'.CName s, loc), kname)
| L.CRecord xcs =>
let
val k = kunif ()
val xcs' = map (fn (x, c) =>
let
val (x', xk) = elabCon env x
val (c', ck) = elabCon env c
in
checkKind env x' xk kname;
checkKind env c' ck k;
(x', c')
end) xcs
in
((L'.CRecord (k, xcs'), loc), (L'.KRecord k, loc))
end
| L.CConcat (c1, c2) =>
let
val (c1', k1) = elabCon env c1
val (c2', k2) = elabCon env c2
val ku = kunif ()
val k = (L'.KRecord ku, loc)
in
checkKind env c1' k1 k;
checkKind env c2' k2 k;
((L'.CConcat (c1', c2'), loc), k)
end
| L.CWild k =>
let
val k' = elabKind k
in
(cunif k', k')
end
fun kunifsRemain k =
case k of
L'.KUnif (_, ref NONE) => true
| _ => false
fun cunifsRemain c =
case c of
L'.CUnif (_, _, ref NONE) => true
| _ => false
val kunifsInKind = U.Kind.exists kunifsRemain
val kunifsInCon = U.Con.exists {kind = kunifsRemain,
con = fn _ => false}
val kunifsInExp = U.Exp.exists {kind = kunifsRemain,
con = fn _ => false,
exp = fn _ => false}
val cunifsInCon = U.Con.exists {kind = fn _ => false,
con = cunifsRemain}
val cunifsInExp = U.Exp.exists {kind = fn _ => false,
con = cunifsRemain,
exp = fn _ => false}
fun occursCon r =
U.Con.exists {kind = fn _ => false,
con = fn L'.CUnif (_, _, r') => r = r'
| _ => false}
datatype cunify_error =
CKind of L'.kind * L'.kind * kunify_error
| COccursCheckFailed of L'.con * L'.con
| CIncompatible of L'.con * L'.con
| CExplicitness of L'.con * L'.con
| CKindof of L'.con
| CRecordFailure
exception CUnify' of cunify_error
fun cunifyError env err =
case err of
CKind (k1, k2, kerr) =>
(eprefaces "Kind unification failure"
[("Kind 1", p_kind k1),
("Kind 2", p_kind k2)];
kunifyError kerr)
| COccursCheckFailed (c1, c2) =>
eprefaces "Constructor occurs check failed"
[("Con 1", p_con env c1),
("Con 2", p_con env c2)]
| CIncompatible (c1, c2) =>
eprefaces "Incompatible constructors"
[("Con 1", p_con env c1),
("Con 2", p_con env c2)]
| CExplicitness (c1, c2) =>
eprefaces "Differing constructor function explicitness"
[("Con 1", p_con env c1),
("Con 2", p_con env c2)]
| CKindof c =>
eprefaces "Kind unification variable blocks kindof calculation"
[("Con", p_con env c)]
| CRecordFailure =>
eprefaces "Can't unify record constructors" []
exception SynUnif = E.SynUnif
val liftConInCon = E.liftConInCon
val subConInCon =
U.Con.mapB {kind = fn k => k,
con = fn (xn, rep) => fn c =>
case c of
L'.CRel xn' =>
if xn = xn' then
#1 rep
else
c
(*| L'.CUnif _ => raise SynUnif*)
| _ => c,
bind = fn ((xn, rep), U.Con.Rel _) => (xn+1, liftConInCon 0 rep)
| (ctx, _) => ctx}
type record_summary = {
fields : (L'.con * L'.con) list,
unifs : (L'.con * L'.con option ref) list,
others : L'.con list
}
fun summaryToCon {fields, unifs, others} =
let
val c = (L'.CRecord (ktype, []), dummy)
val c = List.foldr (fn (c', c) => (L'.CConcat (c', c), dummy)) c others
val c = List.foldr (fn ((c', _), c) => (L'.CConcat (c', c), dummy)) c unifs
in
(L'.CConcat ((L'.CRecord (ktype, fields), dummy), c), dummy)
end
fun p_summary env s = p_con env (summaryToCon s)
exception CUnify of L'.con * L'.con * cunify_error
fun hnormKind (kAll as (k, _)) =
case k of
L'.KUnif (_, ref (SOME k)) => hnormKind k
| _ => kAll
fun kindof env (c, loc) =
case c of
L'.TFun _ => ktype
| L'.TCFun _ => ktype
| L'.TRecord _ => ktype
| L'.CRel xn => #2 (E.lookupCRel env xn)
| L'.CNamed xn => #2 (E.lookupCNamed env xn)
| L'.CApp (c, _) =>
(case #1 (hnormKind (kindof env c)) of
L'.KArrow (_, k) => k
| L'.KError => kerror
| _ => raise CUnify' (CKindof c))
| L'.CAbs (x, k, c) => (L'.KArrow (k, kindof (E.pushCRel env x k) c), loc)
| L'.CName _ => kname
| L'.CRecord (k, _) => (L'.KRecord k, loc)
| L'.CConcat (c, _) => kindof env c
| L'.CError => kerror
| L'.CUnif (k, _, _) => k
fun unifyRecordCons env (c1, c2) =
let
val k1 = kindof env c1
val k2 = kindof env c2
in
unifyKinds k1 k2;
unifySummaries env (k1, recordSummary env c1, recordSummary env c2)
end
and recordSummary env c : record_summary =
case hnormCon env c of
(L'.CRecord (_, xcs), _) => {fields = xcs, unifs = [], others = []}
| (L'.CConcat (c1, c2), _) =>
let
val s1 = recordSummary env c1
val s2 = recordSummary env c2
in
{fields = #fields s1 @ #fields s2,
unifs = #unifs s1 @ #unifs s2,
others = #others s1 @ #others s2}
end
| (L'.CUnif (_, _, ref (SOME c)), _) => recordSummary env c
| c' as (L'.CUnif (_, _, r), _) => {fields = [], unifs = [(c', r)], others = []}
| c' => {fields = [], unifs = [], others = [c']}
and consEq env (c1, c2) =
(unifyCons env c1 c2;
true)
handle CUnify _ => false
and unifySummaries env (k, s1 : record_summary, s2 : record_summary) =
let
(*val () = eprefaces "Summaries" [("#1", p_summary env s1),
("#2", p_summary env s2)]*)
fun eatMatching p (ls1, ls2) =
let
fun em (ls1, ls2, passed1) =
case ls1 of
[] => (rev passed1, ls2)
| h1 :: t1 =>
let
fun search (ls2', passed2) =
case ls2' of
[] => em (t1, ls2, h1 :: passed1)
| h2 :: t2 =>
if p (h1, h2) then
em (t1, List.revAppend (passed2, t2), passed1)
else
search (t2, h2 :: passed2)
in
search (ls2, [])
end
in
em (ls1, ls2, [])
end
val (fs1, fs2) = eatMatching (fn ((x1, c1), (x2, c2)) =>
if consEq env (x1, x2) then
(unifyCons env c1 c2;
true)
else
false) (#fields s1, #fields s2)
(*val () = eprefaces "Summaries2" [("#1", p_summary env {fields = fs1, unifs = #unifs s1, others = #others s1}),
("#2", p_summary env {fields = fs2, unifs = #unifs s2, others = #others s2})]*)
val (unifs1, unifs2) = eatMatching (fn ((_, r1), (_, r2)) => r1 = r2) (#unifs s1, #unifs s2)
val (others1, others2) = eatMatching (consEq env) (#others s1, #others s2)
fun unifFields (fs, others, unifs) =
case (fs, others, unifs) of
([], [], _) => ([], [], unifs)
| (_, _, []) => (fs, others, [])
| (_, _, (_, r) :: rest) =>
let
val r' = ref NONE
val cr' = (L'.CUnif (k, "recd", r'), dummy)
val prefix = case (fs, others) of
([], other :: others) =>
List.foldl (fn (other, c) =>
(L'.CConcat (c, other), dummy))
other others
| (fs, []) =>
(L'.CRecord (k, fs), dummy)
| (fs, others) =>
List.foldl (fn (other, c) =>
(L'.CConcat (c, other), dummy))
(L'.CRecord (k, fs), dummy) others
in
r := SOME (L'.CConcat (prefix, cr'), dummy);
([], [], (cr', r') :: rest)
end
val (fs1, others1, unifs2) = unifFields (fs1, others1, unifs2)
val (fs2, others2, unifs1) = unifFields (fs2, others2, unifs1)
val clear1 = case (fs1, others1) of
([], []) => true
| _ => false
val clear2 = case (fs2, others2) of
([], []) => true
| _ => false
val empty = (L'.CRecord (k, []), dummy)
fun pairOffUnifs (unifs1, unifs2) =
case (unifs1, unifs2) of
([], _) =>
if clear1 then
List.app (fn (_, r) => r := SOME empty) unifs2
else
raise CUnify' CRecordFailure
| (_, []) =>
if clear2 then
List.app (fn (_, r) => r := SOME empty) unifs1
else
raise CUnify' CRecordFailure
| ((c1, _) :: rest1, (_, r2) :: rest2) =>
(r2 := SOME c1;
pairOffUnifs (rest1, rest2))
in
pairOffUnifs (unifs1, unifs2)
end
and hnormCon env (cAll as (c, _)) =
case c of
L'.CUnif (_, _, ref (SOME c)) => hnormCon env c
| L'.CNamed xn =>
(case E.lookupCNamed env xn of
(_, _, SOME c') => hnormCon env c'
| _ => cAll)
| L'.CApp (c1, c2) =>
(case hnormCon env c1 of
(L'.CAbs (_, _, cb), _) =>
((hnormCon env (subConInCon (0, c2) cb))
handle SynUnif => cAll)
| _ => cAll)
| L'.CConcat (c1, c2) =>
(case (hnormCon env c1, hnormCon env c2) of
((L'.CRecord (k, xcs1), loc), (L'.CRecord (_, xcs2), _)) =>
(L'.CRecord (k, xcs1 @ xcs2), loc)
| _ => cAll)
| _ => cAll
and unifyCons' env c1 c2 =
unifyCons'' env (hnormCon env c1) (hnormCon env c2)
and unifyCons'' env (c1All as (c1, _)) (c2All as (c2, _)) =
let
fun err f = raise CUnify' (f (c1All, c2All))
fun isRecord () = unifyRecordCons env (c1All, c2All)
in
case (c1, c2) of
(L'.TFun (d1, r1), L'.TFun (d2, r2)) =>
(unifyCons' env d1 d2;
unifyCons' env r1 r2)
| (L'.TCFun (expl1, x1, d1, r1), L'.TCFun (expl2, _, d2, r2)) =>
if expl1 <> expl2 then
err CExplicitness
else
(unifyKinds d1 d2;
unifyCons' (E.pushCRel env x1 d1) r1 r2)
| (L'.TRecord r1, L'.TRecord r2) => unifyCons' env r1 r2
| (L'.CRel n1, L'.CRel n2) =>
if n1 = n2 then
()
else
err CIncompatible
| (L'.CNamed n1, L'.CNamed n2) =>
if n1 = n2 then
()
else
err CIncompatible
| (L'.CApp (d1, r1), L'.CApp (d2, r2)) =>
(unifyCons' env d1 d2;
unifyCons' env r1 r2)
| (L'.CAbs (x1, k1, c1), L'.CAbs (_, k2, c2)) =>
(unifyKinds k1 k2;
unifyCons' (E.pushCRel env x1 k1) c1 c2)
| (L'.CName n1, L'.CName n2) =>
if n1 = n2 then
()
else
err CIncompatible
| (L'.CError, _) => ()
| (_, L'.CError) => ()
| (L'.CUnif (_, _, ref (SOME c1All)), _) => unifyCons' env c1All c2All
| (_, L'.CUnif (_, _, ref (SOME c2All))) => unifyCons' env c1All c2All
| (L'.CUnif (k1, _, r1), L'.CUnif (k2, _, r2)) =>
if r1 = r2 then
()
else
(unifyKinds k1 k2;
r1 := SOME c2All)
| (L'.CUnif (_, _, r), _) =>
if occursCon r c2All then
err COccursCheckFailed
else
r := SOME c2All
| (_, L'.CUnif (_, _, r)) =>
if occursCon r c1All then
err COccursCheckFailed
else
r := SOME c1All
| (L'.CRecord _, _) => isRecord ()
| (_, L'.CRecord _) => isRecord ()
| (L'.CConcat _, _) => isRecord ()
| (_, L'.CConcat _) => isRecord ()
| _ => err CIncompatible
end
and unifyCons env c1 c2 =
unifyCons' env c1 c2
handle CUnify' err => raise CUnify (c1, c2, err)
| KUnify args => raise CUnify (c1, c2, CKind args)
datatype exp_error =
UnboundExp of ErrorMsg.span * string
| Unify of L'.exp * L'.con * L'.con * cunify_error
| Unif of string * L'.con
| WrongForm of string * L'.exp * L'.con
fun expError env err =
case err of
UnboundExp (loc, s) =>
ErrorMsg.errorAt loc ("Unbound expression variable " ^ s)
| Unify (e, c1, c2, uerr) =>
(ErrorMsg.errorAt (#2 e) "Unification failure";
eprefaces' [("Expression", p_exp env e),
("Have con", p_con env c1),
("Need con", p_con env c2)];
cunifyError env uerr)
| Unif (action, c) =>
(ErrorMsg.errorAt (#2 c) ("Unification variable blocks " ^ action);
eprefaces' [("Con", p_con env c)])
| WrongForm (variety, e, t) =>
(ErrorMsg.errorAt (#2 e) ("Expression is not a " ^ variety);
eprefaces' [("Expression", p_exp env e),
("Type", p_con env t)])
fun checkCon env e c1 c2 =
unifyCons env c1 c2
handle CUnify (c1, c2, err) =>
expError env (Unify (e, c1, c2, err))
fun primType env p =
let
val s = case p of
P.Int _ => "int"
| P.Float _ => "float"
| P.String _ => "string"
in
case E.lookupC env s of
E.NotBound => raise Fail ("Primitive type " ^ s ^ " unbound")
| E.Rel _ => raise Fail ("Primitive type " ^ s ^ " bound as relative")
| E.Named (n, (L'.KType, _)) => L'.CNamed n
| E.Named _ => raise Fail ("Primitive type " ^ s ^ " bound at non-Type kind")
end
fun typeof env (e, loc) =
case e of
L'.EPrim p => (primType env p, loc)
| L'.ERel n => #2 (E.lookupERel env n)
| L'.ENamed n => #2 (E.lookupENamed env n)
| L'.EApp (e1, _) =>
(case #1 (typeof env e1) of
L'.TFun (_, c) => c
| _ => raise Fail "typeof: Bad EApp")
| L'.EAbs (_, _, ran, _) => ran
| L'.ECApp (e1, c) =>
(case #1 (typeof env e1) of
L'.TCFun (_, _, _, c1) => subConInCon (0, c) c1
| _ => raise Fail "typeof: Bad ECApp")
| L'.ECAbs (expl, x, k, e1) => (L'.TCFun (expl, x, k, typeof (E.pushCRel env x k) e1), loc)
| L'.ERecord xes => (L'.TRecord (L'.CRecord (ktype, map (fn (x, _, t) => (x, t)) xes), loc), loc)
| L'.EField (_, _, {field, ...}) => field
| L'.EError => cerror
fun elabHead env (e as (_, loc)) t =
let
fun unravel (t, e) =
case hnormCon env t of
(L'.TCFun (L'.Implicit, x, k, t'), _) =>
let
val u = cunif k
in
unravel (subConInCon (0, u) t',
(L'.ECApp (e, u), loc))
end
| _ => (e, t)
in
unravel (t, e)
end
fun elabExp env (e, loc) =
case e of
L.EAnnot (e, t) =>
let
val (e', et) = elabExp env e
val (t', _) = elabCon env t
in
checkCon env e' et t';
(e', t')
end
| L.EPrim p => ((L'.EPrim p, loc), (primType env p, loc))
| L.EVar s =>
(case E.lookupE env s of
E.NotBound =>
(expError env (UnboundExp (loc, s));
(eerror, cerror))
| E.Rel (n, t) => ((L'.ERel n, loc), t)
| E.Named (n, t) => ((L'.ENamed n, loc), t))
| L.EApp (e1, e2) =>
let
val (e1', t1) = elabExp env e1
val (e1', t1) = elabHead env e1' t1
val (e2', t2) = elabExp env e2
val dom = cunif ktype
val ran = cunif ktype
val t = (L'.TFun (dom, ran), dummy)
in
checkCon env e1' t1 t;
checkCon env e2' t2 dom;
((L'.EApp (e1', e2'), loc), ran)
end
| L.EAbs (x, to, e) =>
let
val t' = case to of
NONE => cunif ktype
| SOME t =>
let
val (t', tk) = elabCon env t
in
checkKind env t' tk ktype;
t'
end
val (e', et) = elabExp (E.pushERel env x t') e
in
((L'.EAbs (x, t', et, e'), loc),
(L'.TFun (t', et), loc))
end
| L.ECApp (e, c) =>
let
val (e', et) = elabExp env e
val (e', et) = elabHead env e' et
val (c', ck) = elabCon env c
in
case #1 (hnormCon env et) of
L'.CError => (eerror, cerror)
| L'.TCFun (_, _, k, eb) =>
let
val () = checkKind env c' ck k
val eb' = subConInCon (0, c') eb
handle SynUnif => (expError env (Unif ("substitution", eb));
cerror)
in
((L'.ECApp (e', c'), loc), eb')
end
| L'.CUnif _ =>
(expError env (Unif ("application", et));
(eerror, cerror))
| _ =>
(expError env (WrongForm ("constructor function", e', et));
(eerror, cerror))
end
| L.ECAbs (expl, x, k, e) =>
let
val expl' = elabExplicitness expl
val k' = elabKind k
val (e', et) = elabExp (E.pushCRel env x k') e
in
((L'.ECAbs (expl', x, k', e'), loc),
(L'.TCFun (expl', x, k', et), loc))
end
| L.ERecord xes =>
let
val xes' = map (fn (x, e) =>
let
val (x', xk) = elabCon env x
val (e', et) = elabExp env e
in
checkKind env x' xk kname;
(x', e', et)
end) xes
in
((L'.ERecord xes', loc),
(L'.TRecord (L'.CRecord (ktype, map (fn (x', _, et) => (x', et)) xes'), loc), loc))
end
| L.EField (e, c) =>
let
val (e', et) = elabExp env e
val (c', ck) = elabCon env c
val ft = cunif ktype
val rest = cunif ktype_record
in
checkKind env c' ck kname;
checkCon env e' et (L'.TRecord (L'.CConcat ((L'.CRecord (ktype, [(c', ft)]), loc), rest), loc), loc);
((L'.EField (e', c', {field = ft, rest = rest}), loc), ft)
end
datatype decl_error =
KunifsRemainKind of ErrorMsg.span * L'.kind
| KunifsRemainCon of ErrorMsg.span * L'.con
| KunifsRemainExp of ErrorMsg.span * L'.exp
| CunifsRemainCon of ErrorMsg.span * L'.con
| CunifsRemainExp of ErrorMsg.span * L'.exp
fun declError env err =
case err of
KunifsRemainKind (loc, k) =>
(ErrorMsg.errorAt loc "Some kind unification variables are undetermined in kind";
eprefaces' [("Kind", p_kind k)])
| KunifsRemainCon (loc, c) =>
(ErrorMsg.errorAt loc "Some kind unification variables are undetermined in constructor";
eprefaces' [("Constructor", p_con env c)])
| KunifsRemainExp (loc, e) =>
(ErrorMsg.errorAt loc "Some kind unification variables are undetermined in expression";
eprefaces' [("Expression", p_exp env e)])
| CunifsRemainCon (loc, c) =>
(ErrorMsg.errorAt loc "Some constructor unification variables are undetermined in constructor";
eprefaces' [("Constructor", p_con env c)])
| CunifsRemainExp (loc, e) =>
(ErrorMsg.errorAt loc "Some constructor unification variables are undetermined in expression";
eprefaces' [("Expression", p_exp env e)])
datatype sgn_error =
UnboundSgn of ErrorMsg.span * string
| UnmatchedSgi of L'.sgn_item
| SgiWrongKind of L'.sgn_item * L'.kind * L'.sgn_item * L'.kind * kunify_error
| SgiWrongCon of L'.sgn_item * L'.con * L'.sgn_item * L'.con * cunify_error
fun sgnError env err =
case err of
UnboundSgn (loc, s) =>
ErrorMsg.errorAt loc ("Unbound signature variable " ^ s)
| UnmatchedSgi (sgi as (_, loc)) =>
(ErrorMsg.errorAt loc "Unmatched signature item";
eprefaces' [("Item", p_sgn_item env sgi)])
| SgiWrongKind (sgi1, k1, sgi2, k2, kerr) =>
(ErrorMsg.errorAt (#2 sgi1) "Kind unification failure in signature matching:";
eprefaces' [("Item 1", p_sgn_item env sgi1),
("Item 2", p_sgn_item env sgi2),
("Kind 1", p_kind k1),
("Kind 2", p_kind k2)];
kunifyError kerr)
| SgiWrongCon (sgi1, c1, sgi2, c2, cerr) =>
(ErrorMsg.errorAt (#2 sgi1) "Constructor unification failure in signature matching:";
eprefaces' [("Item 1", p_sgn_item env sgi1),
("Item 2", p_sgn_item env sgi2),
("Con 1", p_con env c1),
("Con 2", p_con env c2)];
cunifyError env cerr)
datatype str_error =
UnboundStr of ErrorMsg.span * string
fun strError env err =
case err of
UnboundStr (loc, s) =>
ErrorMsg.errorAt loc ("Unbound structure variable " ^ s)
fun elabSgn_item ((sgi, loc), env) =
let
in
resetKunif ();
resetCunif ();
case sgi of
L.SgiConAbs (x, k) =>
let
val k' = elabKind k
val (env', n) = E.pushCNamed env x k' NONE
in
if ErrorMsg.anyErrors () then
()
else (
if kunifsInKind k' then
declError env (KunifsRemainKind (loc, k'))
else
()
);
((L'.SgiConAbs (x, n, k'), loc), env')
end
| L.SgiCon (x, ko, c) =>
let
val k' = case ko of
NONE => kunif ()
| SOME k => elabKind k
val (c', ck) = elabCon env c
val (env', n) = E.pushCNamed env x k' (SOME c')
in
checkKind env c' ck k';
if ErrorMsg.anyErrors () then
()
else (
if kunifsInKind k' then
declError env (KunifsRemainKind (loc, k'))
else
();
if kunifsInCon c' then
declError env (KunifsRemainCon (loc, c'))
else
()
);
((L'.SgiCon (x, n, k', c'), loc), env')
end
| L.SgiVal (x, c) =>
let
val (c', ck) = elabCon env c
val (env', n) = E.pushENamed env x c'
in
unifyKinds ck ktype;
if ErrorMsg.anyErrors () then
()
else (
if kunifsInCon c' then
declError env (KunifsRemainCon (loc, c'))
else
()
);
((L'.SgiVal (x, n, c'), loc), env')
end
| L.SgiStr (x, sgn) =>
let
val sgn' = elabSgn env sgn
val (env', n) = E.pushStrNamed env x sgn'
in
((L'.SgiStr (x, n, sgn'), loc), env')
end
end
and elabSgn env (sgn, loc) =
case sgn of
L.SgnConst sgis =>
let
val (sgis', _) = ListUtil.foldlMap elabSgn_item env sgis
in
(L'.SgnConst sgis', loc)
end
| L.SgnVar x =>
(case E.lookupSgn env x of
NONE =>
(sgnError env (UnboundSgn (loc, x));
(L'.SgnError, loc))
| SOME (n, sgis) => (L'.SgnVar n, loc))
fun sgiOfDecl (d, loc) =
case d of
L'.DCon (x, n, k, c) => SOME (L'.SgiCon (x, n, k, c), loc)
| L'.DVal (x, n, t, _) => SOME (L'.SgiVal (x, n, t), loc)
| L'.DSgn _ => NONE
| L'.DStr (x, n, sgn, _) => SOME (L'.SgiStr (x, n, sgn), loc)
fun subSgn env (all1 as (sgn1, _)) (all2 as (sgn2, loc2)) =
case (sgn1, sgn2) of
(L'.SgnError, _) => ()
| (_, L'.SgnError) => ()
| (L'.SgnVar n, _) =>
subSgn env (#2 (E.lookupSgnNamed env n)) all2
| (_, L'.SgnVar n) =>
subSgn env all1 (#2 (E.lookupSgnNamed env n))
| (L'.SgnConst sgis1, L'.SgnConst sgis2) =>
let
fun folder (sgi2All as (sgi, _), env) =
let
fun seek p =
let
fun seek env ls =
case ls of
[] => (sgnError env (UnmatchedSgi sgi2All);
env)
| h :: t =>
case p h of
NONE => seek (E.sgiBinds env h) t
| SOME env => env
in
seek env sgis1
end
in
case sgi of
L'.SgiConAbs (x, n2, k2) =>
seek (fn sgi1All as (sgi1, _) =>
let
fun found (x, n1, k1, co1) =
let
val () = unifyKinds k1 k2
handle KUnify (k1, k2, err) =>
sgnError env (SgiWrongKind (sgi1All, k1, sgi2All, k2, err))
val env = E.pushCNamedAs env x n1 k1 co1
in
SOME (if n1 = n2 then
env
else
E.pushCNamedAs env x n2 k2 (SOME (L'.CNamed n1, loc2)))
end
in
case sgi1 of
L'.SgiConAbs (x, n1, k1) => found (x, n1, k1, NONE)
| L'.SgiCon (x, n1, k1, c1) => found (x, n1, k1, SOME c1)
| _ => NONE
end)
| L'.SgiCon (x, n2, k2, c2) =>
seek (fn sgi1All as (sgi1, _) =>
case sgi1 of
L'.SgiCon (x, n1, k1, c1) =>
let
val () = unifyCons env c1 c2
handle CUnify (c1, c2, err) =>
sgnError env (SgiWrongCon (sgi1All, c1, sgi2All, c2, err))
in
SOME (E.pushCNamedAs env x n2 k2 (SOME c2))
end
| _ => NONE)
| L'.SgiVal (x, n2, c2) =>
seek (fn sgi1All as (sgi1, _) =>
case sgi1 of
L'.SgiVal (x, n1, c1) =>
let
val () = unifyCons env c1 c2
handle CUnify (c1, c2, err) =>
sgnError env (SgiWrongCon (sgi1All, c1, sgi2All, c2, err))
in
SOME env
end
| _ => NONE)
| _ => raise Fail "Not ready for more sig matching"
end
in
ignore (foldl folder env sgis2)
end
fun elabDecl ((d, loc), env) =
let
in
resetKunif ();
resetCunif ();
case d of
L.DCon (x, ko, c) =>
let
val k' = case ko of
NONE => kunif ()
| SOME k => elabKind k
val (c', ck) = elabCon env c
val (env', n) = E.pushCNamed env x k' (SOME c')
in
checkKind env c' ck k';
if ErrorMsg.anyErrors () then
()
else (
if kunifsInKind k' then
declError env (KunifsRemainKind (loc, k'))
else
();
if kunifsInCon c' then
declError env (KunifsRemainCon (loc, c'))
else
()
);
((L'.DCon (x, n, k', c'), loc), env')
end
| L.DVal (x, co, e) =>
let
val (c', ck) = case co of
NONE => (cunif ktype, ktype)
| SOME c => elabCon env c
val (e', et) = elabExp env e
val (env', n) = E.pushENamed env x c'
in
checkCon env e' et c';
if ErrorMsg.anyErrors () then
()
else (
if kunifsInCon c' then
declError env (KunifsRemainCon (loc, c'))
else
();
if cunifsInCon c' then
declError env (CunifsRemainCon (loc, c'))
else
();
if kunifsInExp e' then
declError env (KunifsRemainExp (loc, e'))
else
();
if cunifsInExp e' then
declError env (CunifsRemainExp (loc, e'))
else
());
((L'.DVal (x, n, c', e'), loc), env')
end
| L.DSgn (x, sgn) =>
let
val sgn' = elabSgn env sgn
val (env', n) = E.pushSgnNamed env x sgn'
in
((L'.DSgn (x, n, sgn'), loc), env')
end
| L.DStr (x, sgno, str) =>
let
val formal = Option.map (elabSgn env) sgno
val (str', actual) = elabStr env str
val sgn' = case formal of
NONE => actual
| SOME formal =>
(subSgn env actual formal;
formal)
val (env', n) = E.pushStrNamed env x sgn'
in
((L'.DStr (x, n, sgn', str'), loc), env')
end
end
and elabStr env (str, loc) =
case str of
L.StrConst ds =>
let
val (ds', env') = ListUtil.foldlMap elabDecl env ds
val sgis = List.mapPartial sgiOfDecl ds'
in
((L'.StrConst ds', loc), (L'.SgnConst sgis, loc))
end
| L.StrVar x =>
(case E.lookupStr env x of
NONE =>
(strError env (UnboundStr (loc, x));
(strerror, sgnerror))
| SOME (n, sgn) => ((L'.StrVar n, loc), sgn))
val elabFile = ListUtil.foldlMap elabDecl
end
|