function serialize(oNode, iParentPrecedence) {
				var sFilter;

				if (!oNode) {
					return "";
				}
				if (oNode.parameters) {
					sFilter = oNode.parameters.map(function (oParameter) {
						return serialize(oParameter, 0);
					}).join(",");
					return oNode.value + "(" + sFilter + ")";
				}
				sFilter = serialize(oNode.left, oNode.precedence) + oNode.value
					+ serialize(oNode.right, oNode.precedence);
				if (oNode.precedence < iParentPrecedence) {
					sFilter = "(" + sFilter + ")";
				}
				return sFilter;
			}
Builds the filter string.

@param {object} oSyntaxTree The syntax tree
@returns {string} The filter string