function getNumberCodeRanges(numType) {
			if (numType === 'x' || numType === 'X') {
				this.index += 2;
				return [
					[48, 57], // 0-9
					[65, 70], // A-F
					[97, 102], // a-f
				];
			}
			else if (numType === 'b' || numType === 'B') {
				this.index += 2;
				return [[48, 49]]; // 0-1
			}
			else if (numType === 'o' || numType === 'O' ||
				(numType >= '0' && numType <= '7')) { // 0-7 allows non-standard 0644 = 420
				this.index += numType <= '7' ? 1 : 2;
				return [[48, 55]]; // 0-7
			}
			return null;
		}
Gets the range of allowable number codes (decimal) and updates index
@param {string} numType
@returns {number[][]|null}