public override void Gen(TypeBuilder program, MethodBuilder method)
{
AstNode left = this.child;
AstNode right = left.sibling;
left.Gen(program, method);
right.Gen(program, method);
if (this.symbol == "+") {
method.GetILGenerator().EmitCall(OpCodes.Callvirt, typeof(TypeBase).GetMethod("Add"), new Type[] { typeof(TypeBase) });
} else if (this.symbol == "-") {
method.GetILGenerator().EmitCall(OpCodes.Callvirt,typeof(TypeBase).GetMethod("Minus"), new Type[] { typeof(TypeBase) });
}
}