	filterChain: function() {
		var left = this.expression();
		while (this.expect("|")) {
			left = this.filter(left);
		}
		return left;
	},
The software constructs all or part of a command, data structure, or record using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify how it is parsed or interpreted when it is sent to a downstream component.