--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/flat_util.sml	Tue Jun 10 15:56:33 2008 -0400
@@ -0,0 +1,286 @@
+(* 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 FlatUtil :> FLAT_UTIL = struct
+
+open Flat
+
+structure S = Search
+
+structure Typ = struct
+
+fun mapfold fc =
+    let
+        fun mft c acc =
+            S.bindP (mft' c acc, fc)
+
+        and mft' (cAll as (c, loc)) =
+            case c of
+                TFun (t1, t2) =>
+                S.bind2 (mft t1,
+                      fn t1' =>
+                         S.map2 (mft t2,
+                              fn t2' =>
+                                 (TFun (t1', t2'), loc)))
+              | TCode (t1, t2) =>
+                S.bind2 (mft t1,
+                      fn t1' =>
+                         S.map2 (mft t2,
+                              fn t2' =>
+                                 (TCode (t1', t2'), loc)))
+              | TRecord xts =>
+                S.map2 (ListUtil.mapfold (fn (x, t) =>
+                                             S.map2 (mft t,
+                                                  fn t' =>
+                                                     (x, t')))
+                                         xts,
+                     fn xts' => (TRecord xts', loc))
+              | TNamed _ => S.return2 cAll
+    in
+        mft
+    end
+
+fun map typ c =
+    case mapfold (fn c => fn () => S.Continue (typ c, ())) c () of
+        S.Return () => raise Fail "Flat_util.Typ.map"
+      | S.Continue (c, ()) => c
+
+fun fold typ s c =
+    case mapfold (fn c => fn s => S.Continue (c, typ (c, s))) c s of
+        S.Continue (_, s) => s
+      | S.Return _ => raise Fail "FlatUtil.Typ.fold: Impossible"
+
+fun exists typ k =
+    case mapfold (fn c => fn () =>
+                             if typ c then
+                                 S.Return ()
+                             else
+                                 S.Continue (c, ())) k () of
+        S.Return _ => true
+      | S.Continue _ => false
+
+end
+
+structure Exp = struct
+
+datatype binder =
+         NamedT of string * int * typ option
+       | RelE of string * typ
+       | NamedE of string * int * typ * exp option
+
+fun mapfoldB {typ = fc, exp = fe, bind} =
+    let
+        val mft = Typ.mapfold fc
+
+        fun mfe ctx e acc =
+            S.bindP (mfe' ctx e acc, fe ctx)
+
+        and mfe' ctx (eAll as (e, loc)) =
+            case e of
+                EPrim _ => S.return2 eAll
+              | ERel _ => S.return2 eAll
+              | ENamed _ => S.return2 eAll
+              | ECode _ => S.return2 eAll
+              | EApp (e1, e2) =>
+                S.bind2 (mfe ctx e1,
+                     fn e1' =>
+                        S.map2 (mfe ctx e2,
+                             fn e2' =>
+                                (EApp (e1', e2'), loc)))
+
+              | ERecord xes =>
+                S.map2 (ListUtil.mapfold (fn (x, e) =>
+                                             S.map2 (mfe ctx e,
+                                                  fn e' =>
+                                                     (x, e')))
+                                         xes,
+                     fn xes' =>
+                        (ERecord xes', loc))
+              | EField (e, x) =>
+                S.map2 (mfe ctx e,
+                      fn e' =>
+                         (EField (e', x), loc))
+
+              | ELet (xes, e) =>
+                S.bind2 (ListUtil.mapfold (fn (x, e) =>
+                                              S.map2 (mfe ctx e,
+                                                   fn e' =>
+                                                      (x, e')))
+                                          xes,
+                      fn xes' =>
+                         S.map2 (mfe ctx e,
+                                 fn e' =>
+                                    (ELet (xes', e'), loc)))
+    in
+        mfe
+    end
+
+fun mapfold {typ = fc, exp = fe} =
+    mapfoldB {typ = fc,
+              exp = fn () => fe,
+              bind = fn ((), _) => ()} ()
+
+fun mapB {typ, exp, bind} ctx e =
+    case mapfoldB {typ = fn c => fn () => S.Continue (typ c, ()),
+                   exp = fn ctx => fn e => fn () => S.Continue (exp ctx e, ()),
+                   bind = bind} ctx e () of
+        S.Continue (e, ()) => e
+      | S.Return _ => raise Fail "FlatUtil.Exp.mapB: Impossible"
+
+fun map {typ, exp} e =
+    case mapfold {typ = fn c => fn () => S.Continue (typ c, ()),
+                  exp = fn e => fn () => S.Continue (exp e, ())} e () of
+        S.Return () => raise Fail "Flat_util.Exp.map"
+      | S.Continue (e, ()) => e
+
+fun fold {typ, exp} s e =
+    case mapfold {typ = fn c => fn s => S.Continue (c, typ (c, s)),
+                  exp = fn e => fn s => S.Continue (e, exp (e, s))} e s of
+        S.Continue (_, s) => s
+      | S.Return _ => raise Fail "FlatUtil.Exp.fold: Impossible"
+
+fun exists {typ, exp} k =
+    case mapfold {typ = fn c => fn () =>
+                                    if typ c then
+                                        S.Return ()
+                                    else
+                                        S.Continue (c, ()),
+                  exp = fn e => fn () =>
+                                    if exp e then
+                                        S.Return ()
+                                    else
+                                        S.Continue (e, ())} k () of
+        S.Return _ => true
+      | S.Continue _ => false
+
+end
+
+structure Decl = struct
+
+datatype binder = datatype Exp.binder
+
+fun mapfoldB {typ = fc, exp = fe, decl = fd, bind} =
+    let
+        val mft = Typ.mapfold fc
+
+        val mfe = Exp.mapfoldB {typ = fc, exp = fe, bind = bind}
+
+        fun mfd ctx d acc =
+            S.bindP (mfd' ctx d acc, fd ctx)
+
+        and mfd' ctx (dAll as (d, loc)) =
+            case d of
+                DVal (x, n, t, e) =>
+                S.bind2 (mft t,
+                      fn t' =>
+                         S.map2 (mfe ctx e,
+                              fn e' =>
+                                 (DVal (x, n, t', e'), loc)))
+              | DFun (n, x, dom, ran, e) =>
+                S.bind2 (mft dom,
+                      fn dom' =>
+                         S.bind2 (mft ran,
+                               fn ran' =>
+                                  S.map2 (mfe ctx e,
+                                       fn e' =>
+                                          (DFun (n, x, dom', ran', e'), loc))))
+    in
+        mfd
+    end    
+
+fun mapfold {typ = fc, exp = fe, decl = fd} =
+    mapfoldB {typ = fc,
+              exp = fn () => fe,
+              decl = fn () => fd,
+              bind = fn ((), _) => ()} ()
+
+fun fold {typ, exp, decl} s d =
+    case mapfold {typ = fn c => fn s => S.Continue (c, typ (c, s)),
+                  exp = fn e => fn s => S.Continue (e, exp (e, s)),
+                  decl = fn d => fn s => S.Continue (d, decl (d, s))} d s of
+        S.Continue (_, s) => s
+      | S.Return _ => raise Fail "FlatUtil.Decl.fold: Impossible"
+
+end
+
+structure File = struct
+
+datatype binder =
+         NamedT of string * int * typ option
+       | RelE of string * typ
+       | NamedE of string * int * typ * exp option
+       | F of int * string * Flat.typ * Flat.typ * Flat.exp
+
+fun mapfoldB (all as {bind, ...}) =
+    let
+        val mfd = Decl.mapfoldB all
+
+        fun mff ctx ds =
+            case ds of
+                nil => S.return2 nil
+              | d :: ds' =>
+                S.bind2 (mfd ctx d,
+                         fn d' =>
+                            let
+                                val b =
+                                    case #1 d' of
+                                        DVal (x, n, t, e) => NamedE (x, n, t, SOME e)
+                                      | DFun v => F v
+                                val ctx' = bind (ctx, b)
+                            in
+                                S.map2 (mff ctx' ds',
+                                     fn ds' =>
+                                        d' :: ds')
+                            end)
+    in
+        mff
+    end
+
+fun mapfold {typ = fc, exp = fe, decl = fd} =
+    mapfoldB {typ = fc,
+              exp = fn () => fe,
+              decl = fn () => fd,
+              bind = fn ((), _) => ()} ()
+
+fun mapB {typ, exp, decl, bind} ctx ds =
+    case mapfoldB {typ = fn c => fn () => S.Continue (typ c, ()),
+                   exp = fn ctx => fn e => fn () => S.Continue (exp ctx e, ()),
+                   decl = fn ctx => fn d => fn () => S.Continue (decl ctx d, ()),
+                   bind = bind} ctx ds () of
+        S.Continue (ds, ()) => ds
+      | S.Return _ => raise Fail "FlatUtil.File.mapB: Impossible"
+
+fun fold {typ, exp, decl} s d =
+    case mapfold {typ = fn c => fn s => S.Continue (c, typ (c, s)),
+                  exp = fn e => fn s => S.Continue (e, exp (e, s)),
+                  decl = fn d => fn s => S.Continue (d, decl (d, s))} d s of
+        S.Continue (_, s) => s
+      | S.Return _ => raise Fail "FlatUtil.File.fold: Impossible"
+
+end
+
+end