--- /dev/null
+(* 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 *)
+
+signature ENV = sig
+
+ type env
+ val empty : env
+
+ val bindType : env -> string -> env
+ val bindVal : env -> string * Ast.typ * Ast.exp option -> env
+
+ val lookupType : env -> string -> bool
+ val lookupVal : env -> string -> Ast.typ option
+ val lookupEquation : env -> string -> Ast.exp option
+
+end