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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.
*)
(* Simplify a Core program algebraically *)
structure Reduce :> REDUCE = struct
open Core
structure IM = IntBinaryMap
datatype env_item =
UnknownK
| KnownK of kind
| UnknownC
| KnownC of con
| UnknownE
| KnownE of exp
| Lift of int * int * int
type env = env_item list
fun ei2s ei =
case ei of
UnknownK => "UK"
| KnownK _ => "KK"
| UnknownC => "UC"
| KnownC _ => "KC"
| UnknownE => "UE"
| KnownE _ => "KE"
| Lift (_, n1, n2) => "(" ^ Int.toString n1 ^ ", " ^ Int.toString n2 ^ ")"
fun e2s env = String.concatWith " " (map ei2s env)
val deKnown = List.filter (fn KnownC _ => false
| KnownE _ => false
| KnownK _ => false
| _ => true)
fun kindConAndExp (namedC, namedE) =
let
fun kind env (all as (k, loc)) =
case k of
KType => all
| KArrow (k1, k2) => (KArrow (kind env k1, kind env k2), loc)
| KName => all
| KRecord k => (KRecord (kind env k), loc)
| KUnit => all
| KTuple ks => (KTuple (map (kind env) ks), loc)
| KRel n =>
let
fun find (n', env, nudge, lift) =
case env of
[] => raise Fail "Reduce.kind: KRel"
| UnknownC :: rest => find (n', rest, nudge, lift)
| KnownC _ :: rest => find (n', rest, nudge, lift)
| UnknownE :: rest => find (n', rest, nudge, lift)
| KnownE _ :: rest => find (n', rest, nudge, lift)
| Lift (lift', _, _) :: rest => find (n', rest, nudge + lift', lift + lift')
| UnknownK :: rest =>
if n' = 0 then
(KRel (n + nudge), loc)
else
find (n' - 1, rest, nudge, lift + 1)
| KnownK k :: rest =>
if n' = 0 then
kind (Lift (lift, 0, 0) :: rest) k
else
find (n' - 1, rest, nudge - 1, lift)
in
find (n, env, 0, 0)
end
| KFun (x, k) => (KFun (x, kind (UnknownK :: env) k), loc)
fun con env (all as (c, loc)) =
((*Print.prefaces "con" [("c", CorePrint.p_con CoreEnv.empty all)];*)
case c of
TFun (c1, c2) => (TFun (con env c1, con env c2), loc)
| TCFun (x, k, c2) => (TCFun (x, kind env k, con (UnknownC :: env) c2), loc)
| TKFun (x, c2) => (TKFun (x, con (UnknownK :: env) c2), loc)
| TRecord c => (TRecord (con env c), loc)
| CRel n =>
let
fun find (n', env, nudge, liftK, liftC) =
case env of
[] => raise Fail "Reduce.con: CRel"
| UnknownK :: rest => find (n', rest, nudge, liftK + 1, liftC)
| KnownK _ :: rest => find (n', rest, nudge, liftK, liftC)
| UnknownE :: rest => find (n', rest, nudge, liftK, liftC)
| KnownE _ :: rest => find (n', rest, nudge, liftK, liftC)
| Lift (liftK', liftC', _) :: rest => find (n', rest, nudge + liftC',
liftK + liftK', liftC + liftC')
| UnknownC :: rest =>
if n' = 0 then
(CRel (n + nudge), loc)
else
find (n' - 1, rest, nudge, liftK, liftC + 1)
| KnownC c :: rest =>
if n' = 0 then
con (Lift (liftK, liftC, 0) :: rest) c
else
find (n' - 1, rest, nudge - 1, liftK, liftC)
in
(*print (Int.toString n ^ ": " ^ e2s env ^ "\n");*)
find (n, env, 0, 0, 0)
end
| CNamed n =>
(case IM.find (namedC, n) of
NONE => all
| SOME c => c)
| CFfi _ => all
| CApp (c1, c2) =>
let
val c1 = con env c1
val c2 = con env c2
in
case #1 c1 of
CAbs (_, _, b) =>
con (KnownC c2 :: deKnown env) b
| CApp ((CMap (dom, ran), _), f) =>
(case #1 c2 of
CRecord (_, []) => (CRecord (kind env ran, []), loc)
| CRecord (_, (x, c) :: rest) =>
con (deKnown env)
(CConcat ((CRecord (ran, [(x, (CApp (f, c), loc))]), loc),
(CApp (c1, (CRecord (kind env dom, rest), loc)), loc)), loc)
| _ => (CApp (c1, c2), loc))
| _ => (CApp (c1, c2), loc)
end
| CAbs (x, k, b) => (CAbs (x, kind env k, con (UnknownC :: env) b), loc)
| CKApp (c1, k) =>
let
val c1 = con env c1
in
case #1 c1 of
CKAbs (_, b) =>
con (KnownK k :: deKnown env) b
| _ => (CKApp (c1, kind env k), loc)
end
| CKAbs (x, b) => (CKAbs (x, con (UnknownK :: env) b), loc)
| CName _ => all
| CRecord (k, xcs) => (CRecord (kind env k, map (fn (x, c) => (con env x, con env c)) xcs), loc)
| CConcat (c1, c2) =>
let
val c1 = con env c1
val c2 = con env c2
in
case (#1 c1, #1 c2) of
(CRecord (k, xcs1), CRecord (_, xcs2)) =>
(CRecord (kind env k, xcs1 @ xcs2), loc)
| _ => (CConcat (c1, c2), loc)
end
| CMap (dom, ran) => (CMap (kind env dom, kind env ran), loc)
| CUnit => all
| CTuple cs => (CTuple (map (con env) cs), loc)
| CProj (c, n) =>
let
val c = con env c
in
case #1 c of
CTuple cs => List.nth (cs, n - 1)
| _ => (CProj (c, n), loc)
end)
fun patCon pc =
case pc of
PConVar _ => pc
| PConFfi {mod = m, datatyp, params, con = c, arg, kind} =>
PConFfi {mod = m, datatyp = datatyp, params = params, con = c,
arg = Option.map (con (map (fn _ => UnknownC) params)) arg,
kind = kind}
val k = (KType, ErrorMsg.dummySpan)
fun doPart e (this as (x, t), rest) =
((x, (EField (e, x, {field = t, rest = (CRecord (k, rest), #2 t)}), #2 t), t),
this :: rest)
fun exp env (all as (e, loc)) =
((*Print.prefaces "exp" [("e", CorePrint.p_exp CoreEnv.empty all),
("env", Print.PD.string (e2s env))];*)
case e of
EPrim _ => all
| ERel n =>
let
fun find (n', env, nudge, liftK, liftC, liftE) =
case env of
[] => raise Fail "Reduce.exp: ERel"
| UnknownK :: rest => find (n', rest, nudge, liftK + 1, liftC, liftE)
| KnownK _ :: rest => find (n', rest, nudge, liftK, liftC, liftE)
| UnknownC :: rest => find (n', rest, nudge, liftK, liftC + 1, liftE)
| KnownC _ :: rest => find (n', rest, nudge, liftK, liftC, liftE)
| Lift (liftK', liftC', liftE') :: rest =>
find (n', rest, nudge + liftE',
liftK + liftK', liftC + liftC', liftE + liftE')
| UnknownE :: rest =>
if n' = 0 then
(ERel (n + nudge), loc)
else
find (n' - 1, rest, nudge, liftK, liftC, liftE + 1)
| KnownE e :: rest =>
if n' = 0 then
((*print "SUBSTITUTING\n";*)
exp (Lift (liftK, liftC, liftE) :: rest) e)
else
find (n' - 1, rest, nudge - 1, liftK, liftC, liftE)
in
(*print (Int.toString n ^ ": " ^ e2s env ^ "\n");*)
find (n, env, 0, 0, 0, 0)
end
| ENamed n =>
(case IM.find (namedE, n) of
NONE => all
| SOME e => e)
| ECon (dk, pc, cs, eo) => (ECon (dk, patCon pc,
map (con env) cs, Option.map (exp env) eo), loc)
| EFfi _ => all
| EFfiApp (m, f, es) => (EFfiApp (m, f, map (exp env) es), loc)
| EApp (e1, e2) =>
let
val e1 = exp env e1
val e2 = exp env e2
in
case #1 e1 of
EAbs (_, _, _, b) => exp (KnownE e2 :: deKnown env) b
| _ => (EApp (e1, e2), loc)
end
| EAbs (x, dom, ran, e) => (EAbs (x, con env dom, con env ran, exp (UnknownE :: env) e), loc)
| ECApp (e, c) =>
let
val e = exp env e
val c = con env c
in
case #1 e of
ECAbs (_, _, b) => exp (KnownC c :: deKnown env) b
| _ => (ECApp (e, c), loc)
end
| ECAbs (x, k, e) => (ECAbs (x, kind env k, exp (UnknownC :: env) e), loc)
| EKApp (e, k) =>
let
val e = exp env e
in
case #1 e of
EKAbs (_, b) => exp (KnownK k :: deKnown env) b
| _ => (EKApp (e, kind env k), loc)
end
| EKAbs (x, e) => (EKAbs (x, exp (UnknownK :: env) e), loc)
| ERecord xcs => (ERecord (map (fn (x, e, t) => (con env x, exp env e, con env t)) xcs), loc)
| EField (e, c, {field, rest}) =>
let
val e = exp env e
val c = con env c
fun default () = (EField (e, c, {field = con env field, rest = con env rest}), loc)
in
case (#1 e, #1 c) of
(ERecord xcs, CName x) =>
(case List.find (fn ((CName x', _), _, _) => x' = x | _ => false) xcs of
NONE => default ()
| SOME (_, e, _) => e)
| _ => default ()
end
| EConcat (e1, c1, e2, c2) =>
let
val e1 = exp env e1
val e2 = exp env e2
in
case (#1 e1, #1 e2) of
(ERecord xes1, ERecord xes2) => (ERecord (xes1 @ xes2), loc)
| _ =>
let
val c1 = con env c1
val c2 = con env c2
in
case (#1 c1, #1 c2) of
(CRecord (k, xcs1), CRecord (_, xcs2)) =>
let
val (xes1, rest) = ListUtil.foldlMap (doPart e1) [] xcs1
val (xes2, _) = ListUtil.foldlMap (doPart e2) rest xcs2
in
exp (deKnown env) (ERecord (xes1 @ xes2), loc)
end
| _ => (EConcat (e1, c1, e2, c2), loc)
end
end
| ECut (e, c, {field, rest}) =>
let
val e = exp env e
val c = con env c
fun default () =
let
val rest = con env rest
in
case #1 rest of
CRecord (k, xcs) =>
let
val (xes, _) = ListUtil.foldlMap (doPart e) [] xcs
in
exp (deKnown env) (ERecord xes, loc)
end
| _ => (ECut (e, c, {field = con env field, rest = rest}), loc)
end
in
case (#1 e, #1 c) of
(ERecord xes, CName x) =>
if List.all (fn ((CName _, _), _, _) => true | _ => false) xes then
(ERecord (List.filter (fn ((CName x', _), _, _) => x' <> x
| _ => raise Fail "Reduce: ECut") xes), loc)
else
default ()
| _ => default ()
end
| ECutMulti (e, c, {rest}) =>
let
val e = exp env e
val c = con env c
fun default () =
let
val rest = con env rest
in
case #1 rest of
CRecord (k, xcs) =>
let
val (xes, _) = ListUtil.foldlMap (doPart e) [] xcs
in
exp (deKnown env) (ERecord xes, loc)
end
| _ => (ECutMulti (e, c, {rest = rest}), loc)
end
in
case (#1 e, #1 c) of
(ERecord xes, CRecord (_, xcs)) =>
if List.all (fn ((CName _, _), _, _) => true | _ => false) xes
andalso List.all (fn ((CName _, _), _) => true | _ => false) xcs then
(ERecord (List.filter (fn ((CName x', _), _, _) =>
List.all (fn ((CName x, _), _) => x' <> x
| _ => raise Fail "Reduce: ECutMulti [1]") xcs
| _ => raise Fail "Reduce: ECutMulti [2]") xes), loc)
else
default ()
| _ => default ()
end
| ECase (e, pes, {disc, result}) =>
let
fun patBinds (p, _) =
case p of
PWild => 0
| PVar _ => 1
| PPrim _ => 0
| PCon (_, _, _, NONE) => 0
| PCon (_, _, _, SOME p) => patBinds p
| PRecord xpts => foldl (fn ((_, p, _), n) => n + patBinds p) 0 xpts
fun pat (all as (p, loc)) =
case p of
PWild => all
| PVar (x, t) => (PVar (x, con env t), loc)
| PPrim _ => all
| PCon (dk, pc, cs, po) =>
(PCon (dk, patCon pc, map (con env) cs, Option.map pat po), loc)
| PRecord xpts => (PRecord (map (fn (x, p, t) => (x, pat p, con env t)) xpts), loc)
in
(ECase (exp env e,
map (fn (p, e) => (pat p,
exp (List.tabulate (patBinds p, fn _ => UnknownE) @ env) e))
pes, {disc = con env disc, result = con env result}), loc)
end
| EWrite e => (EWrite (exp env e), loc)
| EClosure (n, es) => (EClosure (n, map (exp env) es), loc)
| ELet (x, t, e1, e2) => (ELet (x, con env t, exp env e1, exp (UnknownE :: env) e2), loc)
| EServerCall (n, es, e, t) => (EServerCall (n, map (exp env) es, exp env e, con env t), loc))
in
{kind = kind, con = con, exp = exp}
end
fun kind namedC env k = #kind (kindConAndExp (namedC, IM.empty)) env k
fun con namedC env c = #con (kindConAndExp (namedC, IM.empty)) env c
fun exp (namedC, namedE) env e = #exp (kindConAndExp (namedC, namedE)) env e
fun reduce file =
let
fun doDecl (d as (_, loc), st as (namedC, namedE)) =
case #1 d of
DCon (x, n, k, c) =>
let
val k = kind namedC [] k
val c = con namedC [] c
in
((DCon (x, n, k, c), loc),
(IM.insert (namedC, n, c), namedE))
end
| DDatatype (x, n, ps, cs) =>
let
val env = map (fn _ => UnknownC) ps
in
((DDatatype (x, n, ps, map (fn (x, n, co) => (x, n, Option.map (con namedC env) co)) cs), loc),
st)
end
| DVal (x, n, t, e, s) =>
let
val t = con namedC [] t
val e = exp (namedC, namedE) [] e
in
((DVal (x, n, t, e, s), loc),
(namedC, IM.insert (namedE, n, e)))
end
| DValRec vis =>
((DValRec (map (fn (x, n, t, e, s) => (x, n, con namedC [] t, exp (namedC, namedE) [] e, s)) vis), loc),
st)
| DExport _ => (d, st)
| DTable (s, n, c, s', e) => ((DTable (s, n, con namedC [] c, s',
exp (namedC, namedE) [] e), loc), st)
| DSequence _ => (d, st)
| DDatabase _ => (d, st)
| DCookie (s, n, c, s') => ((DCookie (s, n, con namedC [] c, s'), loc), st)
val (file, _) = ListUtil.foldlMap doDecl (IM.empty, IM.empty) file
in
file
end
end
|