--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/expr.h	Wed Oct 22 04:51:16 2008 +0000
@@ -0,0 +1,75 @@
+/*
+expr.h
+Copyright © 2008 William Astle
+
+This file is part of LWASM.
+
+LWASM 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 3 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, see <http://www.gnu.org/licenses/>.
+*/
+
+/*
+This file contains definitions associated with the expression evaluator used
+by LWASM.
+
+The core of the entire expression handler is the opaque type LWVAL, pointers
+to which are passed around to keep track of values. A value may be a simple
+integer or it could be a more complex expression linked by operators or it
+could be a polynomial expression. Simple integers are merely a degenerate
+case of polynomials.
+
+The package understands the following operations:
+
+addition
+subtraction
+multiplication
+division
+modulus
+parentheses
+unary negation
+unary "positive"
+bitwise and
+bitwise or
+bitwise not (1's complement)
+bitwise exclusive or
+
+Infix operators can be expressed as LWVAL <op> LWVAL. Thus, the order of
+operations is only relevant when initially parsing the expression. The order
+of evaluation is determined by what appears on either side of the <op> as
+an LWVAL may be an expression.
+*/
+
+typedef union lwval LWVAL;
+
+struct lwval_int
+{
+	int	lwval_type;					// type of value
+	int lwval_int_value;			// integer value
+};
+
+union lwval
+{
+	struct lwval_int lwval_type_int;	// integer type
+};
+
+enum lwval_types
+{
+	LWVAL_TYPE_INT
+};
+
+#ifndef __expr_h_seen__
+#define __expr_h_seen__
+
+
+
+#endif //__expr_h_seen__