--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/tag.sml	Sun Jul 13 11:43:57 2008 -0400
@@ -0,0 +1,174 @@
+(* 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 Tag :> TAG = struct
+
+open Core
+
+structure U = CoreUtil
+structure E = CoreEnv
+
+structure IM = IntBinaryMap
+
+fun kind (k, s) = (k, s)
+fun con (c, s) = (c, s)
+
+fun exp (e, s) =
+    case e of
+        EApp (
+        (EApp (
+         (EApp (
+          (ECApp (
+           (ECApp (
+            (ECApp (
+             (ECApp (
+              (EFfi ("Basis", "tag"),
+               loc), given), _), absent), _), outer), _), inner), _),
+          attrs), _),
+         tag), _),
+        xml) =>
+        (case attrs of
+             (ERecord xets, _) =>
+             let
+                 val (xets, s) =
+                     ListUtil.foldlMap (fn ((x, e, t), (count, tags, newTags)) =>
+                                           case x of
+                                               (CName "Link", _) =>
+                                               let
+                                                   fun unravel (e, _) =
+                                                       case e of
+                                                           ENamed n => (n, [])
+                                                         | EApp (e1, e2) =>
+                                                           let
+                                                               val (n, es) = unravel e1
+                                                           in
+                                                               (n, es @ [e2])
+                                                           end
+                                                         | _ => (ErrorMsg.errorAt loc "Invalid link expression";
+                                                                 (0, []))
+
+                                                   val (f, args) = unravel e
+
+                                                   val (cn, count, tags, newTags) =
+                                                       case IM.find (tags, f) of
+                                                           NONE =>
+                                                           (count, count + 1, IM.insert (tags, f, count),
+                                                            (f, count) :: newTags)
+                                                         | SOME cn => (cn, count, tags, newTags)
+
+                                                   val e = (EClosure (cn, args), loc)
+                                                   val t = (CFfi ("Basis", "string"), loc)
+                                               in
+                                                   ((x, e, t),
+                                                    (count, tags, newTags))
+                                               end
+                                             | _ => ((x, e, t), (count, tags, newTags)))
+                     s xets
+             in
+                 (EApp (
+                  (EApp (
+                   (EApp (
+                    (ECApp (
+                     (ECApp (
+                      (ECApp (
+                       (ECApp (
+                        (EFfi ("Basis", "tag"),
+                         loc), given), loc), absent), loc), outer), loc), inner), loc),
+                    (ERecord xets, loc)), loc),
+                   tag), loc),
+                  xml), s)
+             end
+           | _ => (ErrorMsg.errorAt loc "Attribute record is too complex";
+                   (e, s)))
+
+      | _ => (e, s)
+
+fun decl (d, s) = (d, s)
+
+fun tag file =
+    let
+        val count = foldl (fn ((d, _), count) =>
+                              case d of
+                                  DCon (_, n, _, _) => Int.max (n, count)
+                                | DVal (_, n, _, _, _) => Int.max (n, count)
+                                | DExport _ => count) 0 file
+
+        fun doDecl (d as (d', loc), (env, count, tags)) =
+            let
+                val (d, (count, tags, newTags)) =
+                    U.Decl.foldMap {kind = kind,
+                                    con = con,
+                                    exp = exp,
+                                    decl = decl}
+                                   (count, tags, []) d
+
+                val env = E.declBinds env d
+
+                val newDs = ListUtil.mapConcat
+                                (fn (f, cn) =>
+                                    let
+                                        fun unravel (all as (t, _)) =
+                                            case t of
+                                                TFun (dom, ran) =>
+                                                let
+                                                    val (args, result) = unravel ran
+                                                in
+                                                    (dom :: args, result)
+                                                end
+                                              | _ => ([], all)
+
+                                        val (fnam, t, _, tag) = E.lookupENamed env f
+                                        val (args, result) = unravel t
+
+                                        val (app, _) = foldl (fn (t, (app, n)) =>
+                                                                 ((EApp (app, (ERel n, loc)), loc),
+                                                                  n - 1))
+                                                             ((ENamed f, loc), length args - 1) args
+                                        val body = (EWrite app, loc)
+                                        val unit = (TRecord (CRecord ((KType, loc), []), loc), loc)
+                                        val (abs, _, t) = foldr (fn (t, (abs, n, rest)) =>
+                                                                    ((EAbs ("x" ^ Int.toString n,
+                                                                            t,
+                                                                            rest,
+                                                                            abs), loc),
+                                                                     n + 1,
+                                                                     (TFun (t, rest), loc)))
+                                                                (body, 0, unit) args
+                                    in
+                                        [(DVal ("wrap_" ^ fnam, cn, t, abs, tag), loc),
+                                         (DExport cn, loc)]
+                                    end) newTags
+            in
+                (newDs @ [d], (env, count, tags))
+            end
+
+        val (file, _) = ListUtil.foldlMapConcat doDecl (CoreEnv.empty, count, IM.empty) file
+    in
+        file
+    end
+
+end