--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/expl_env.sml	Thu Jun 19 10:06:59 2008 -0400
@@ -0,0 +1,267 @@
+(* 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 ExplEnv :> EXPL_ENV = struct
+
+open Expl
+
+structure U = ExplUtil
+
+structure IM = IntBinaryMap
+structure SM = BinaryMapFn(struct
+                           type ord_key = string
+                           val compare = String.compare
+                           end)
+
+exception UnboundRel of int
+exception UnboundNamed of int
+
+
+(* AST utility functions *)
+
+exception SynUnif
+
+val liftConInCon =
+    U.Con.mapB {kind = fn k => k,
+                con = fn bound => fn c =>
+                                     case c of
+                                         CRel xn =>
+                                         if xn < bound then
+                                             c
+                                         else
+                                             CRel (xn + 1)
+                                       (*| CUnif _ => raise SynUnif*)
+                                       | _ => c,
+                bind = fn (bound, U.Con.Rel _) => bound + 1
+                        | (bound, _) => bound}
+
+val lift = liftConInCon 0
+
+
+(* Back to environments *)
+
+datatype 'a var' =
+         Rel' of int * 'a
+       | Named' of int * 'a
+
+datatype 'a var =
+         NotBound
+       | Rel of int * 'a
+       | Named of int * 'a
+
+type env = {
+     renameC : kind var' SM.map,
+     relC : (string * kind) list,
+     namedC : (string * kind * con option) IM.map,
+
+     renameE : con var' SM.map,
+     relE : (string * con) list,
+     namedE : (string * con) IM.map,
+
+     renameSgn : (int * sgn) SM.map,
+     sgn : (string * sgn) IM.map,
+
+     renameStr : (int * sgn) SM.map,
+     str : (string * sgn) IM.map
+}
+
+val namedCounter = ref 0
+
+val empty = {
+    renameC = SM.empty,
+    relC = [],
+    namedC = IM.empty,
+
+    renameE = SM.empty,
+    relE = [],
+    namedE = IM.empty,
+
+    renameSgn = SM.empty,
+    sgn = IM.empty,
+
+    renameStr = SM.empty,
+    str = IM.empty
+}
+
+fun pushCRel (env : env) x k =
+    let
+        val renameC = SM.map (fn Rel' (n, k) => Rel' (n+1, k)
+                               | x => x) (#renameC env)
+    in
+        {renameC = SM.insert (renameC, x, Rel' (0, k)),
+         relC = (x, k) :: #relC env,
+         namedC = IM.map (fn (x, k, co) => (x, k, Option.map lift co)) (#namedC env),
+
+         renameE = #renameE env,
+         relE = map (fn (x, c) => (x, lift c)) (#relE env),
+         namedE = IM.map (fn (x, c) => (x, lift c)) (#namedE env),
+
+         renameSgn = #renameSgn env,
+         sgn = #sgn env,
+
+         renameStr = #renameStr env,
+         str = #str env
+        }
+    end
+
+fun lookupCRel (env : env) n =
+    (List.nth (#relC env, n))
+    handle Subscript => raise UnboundRel n
+
+fun pushCNamed (env : env) x n k co =
+    {renameC = SM.insert (#renameC env, x, Named' (n, k)),
+     relC = #relC env,
+     namedC = IM.insert (#namedC env, n, (x, k, co)),
+
+     renameE = #renameE env,
+     relE = #relE env,
+     namedE = #namedE env,
+
+     renameSgn = #renameSgn env,
+     sgn = #sgn env,
+     
+     renameStr = #renameStr env,
+     str = #str env}
+
+fun lookupCNamed (env : env) n =
+    case IM.find (#namedC env, n) of
+        NONE => raise UnboundNamed n
+      | SOME x => x
+
+fun pushERel (env : env) x t =
+    let
+        val renameE = SM.map (fn Rel' (n, t) => Rel' (n+1, t)
+                               | x => x) (#renameE env)
+    in
+        {renameC = #renameC env,
+         relC = #relC env,
+         namedC = #namedC env,
+
+         renameE = SM.insert (renameE, x, Rel' (0, t)),
+         relE = (x, t) :: #relE env,
+         namedE = #namedE env,
+
+         renameSgn = #renameSgn env,
+         sgn = #sgn env,
+
+         renameStr = #renameStr env,
+         str = #str env}
+    end
+
+fun lookupERel (env : env) n =
+    (List.nth (#relE env, n))
+    handle Subscript => raise UnboundRel n
+
+fun pushENamed (env : env) x n t =
+    {renameC = #renameC env,
+     relC = #relC env,
+     namedC = #namedC env,
+
+     renameE = SM.insert (#renameE env, x, Named' (n, t)),
+     relE = #relE env,
+     namedE = IM.insert (#namedE env, n, (x, t)),
+
+     renameSgn = #renameSgn env,
+     sgn = #sgn env,
+     
+     renameStr = #renameStr env,
+     str = #str env}
+
+fun lookupENamed (env : env) n =
+    case IM.find (#namedE env, n) of
+        NONE => raise UnboundNamed n
+      | SOME x => x
+
+fun pushSgnNamed (env : env) x n sgis =
+    {renameC = #renameC env,
+     relC = #relC env,
+     namedC = #namedC env,
+
+     renameE = #renameE env,
+     relE = #relE env,
+     namedE = #namedE env,
+
+     renameSgn = SM.insert (#renameSgn env, x, (n, sgis)),
+     sgn = IM.insert (#sgn env, n, (x, sgis)),
+     
+     renameStr = #renameStr env,
+     str = #str env}
+
+fun lookupSgnNamed (env : env) n =
+    case IM.find (#sgn env, n) of
+        NONE => raise UnboundNamed n
+      | SOME x => x
+
+fun pushStrNamed (env : env) x n sgis =
+    {renameC = #renameC env,
+     relC = #relC env,
+     namedC = #namedC env,
+
+     renameE = #renameE env,
+     relE = #relE env,
+     namedE = #namedE env,
+
+     renameSgn = #renameSgn env,
+     sgn = #sgn env,
+
+     renameStr = SM.insert (#renameStr env, x, (n, sgis)),
+     str = IM.insert (#str env, n, (x, sgis))}
+
+fun lookupStrNamed (env : env) n =
+    case IM.find (#str env, n) of
+        NONE => raise UnboundNamed n
+      | SOME x => x
+
+fun declBinds env (d, _) =
+    case d of
+        DCon (x, n, k, c) => pushCNamed env x n k (SOME c)
+      | DVal (x, n, t, _) => pushENamed env x n t
+      | DSgn (x, n, sgn) => pushSgnNamed env x n sgn
+      | DStr (x, n, sgn, _) => pushStrNamed env x n sgn
+
+fun sgiBinds env (sgi, _) =
+    case sgi of
+        SgiConAbs (x, n, k) => pushCNamed env x n k NONE
+      | SgiCon (x, n, k, c) => pushCNamed env x n k (SOME c)
+      | SgiVal (x, n, t) => pushENamed env x n t
+      | SgiStr (x, n, sgn) => pushStrNamed env x n sgn
+
+
+val ktype = (KType, ErrorMsg.dummySpan)
+
+fun bbind env x =
+    case ElabEnv.lookupC ElabEnv.basis x of
+        ElabEnv.NotBound => raise Fail "CoreEnv.bbind: Not bound"
+      | ElabEnv.Rel _ => raise Fail "CoreEnv.bbind: Rel"
+      | ElabEnv.Named (n, _) => pushCNamed env x n ktype NONE
+
+val basis = empty
+val basis = bbind basis "int"
+val basis = bbind basis "float"
+val basis = bbind basis "string"
+
+end