Reduction

[hcoop/domtool2.git] / src / env.sml

diff --git a/src/env.sml b/src/env.sml
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+++ b/src/env.sml
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+(* HCoop Domtool (http://hcoop.sourceforge.net/)
+ * Copyright (c) 2006, Adam Chlipala
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+*)
+
+(* Domtool type-checking and reduction environments *)
+
+structure Env :> ENV = struct
+
+open Ast
+
+structure SS = StringSet
+structure SM = StringMap
+
+type env = SS.set * (typ * exp option) SM.map
+val empty : env = (SS.add (SS.singleton "int", "string"),
+                  SM.empty)
+
+fun lookupType (ts, _) name = SS.member (ts, name)
+fun lookupVal (_, vs) name =
+    case SM.find (vs, name) of
+       NONE => NONE
+      | SOME (t, _) => SOME t
+fun lookupEquation (_, vs) name =
+    case SM.find (vs, name) of
+       NONE => NONE
+      | SOME (_, eqo) => eqo
+
+fun bindType (ts, vs) name = (SS.add (ts, name), vs)
+fun bindVal (ts, vs) (name, t, eqo) = (ts, SM.insert (vs, name, (t, eqo)))
+
+end