setLoc(startLine, startColumn, endLine, endColumn) {
		this._locSL = startLine;
		this._locSC = startColumn;
		this._locEL = endLine;
		this._locEC = endColumn;
		this._locI = undefined;
		this._locN = undefined;
		this._loc = undefined;
	}
@param {number} startLine start line
@param {number} startColumn start column
@param {number} endLine end line
@param {number} endColumn end column