private static String parseComplexSequence() {
		//Go to next non-whitespace character
		curChar=peek();
		//Is there a '['?
		if (curChar=='['){
			//Yes, starting with '['! Complex parsing required!
			c++;
			int squareBracketLevel=1;				//square bracket depth level (starting at 1 because there already was '[')
			String result="[";						//result sequence
			//Search ']' which closes the first '['
			while (true){
				if (c<len){
					//Get char
					curChar=lc.charAt(c);
				}else{
					//Next line
					while(l<lines){
						setLine(l+1);
						if (c<len){
							curChar=lc.charAt(c);
							break;
						}
					}
					//End of file reached
					if (l>=lines){
						return result;
					}
				}
				//Add char to result sequence
				result+=curChar;
				//Handle square brackets
				if (curChar=='['){
					//Opening square bracket: increase square bracket level
					squareBracketLevel++;
				}else if (curChar==']'){
					//Closing square bracket: decrease square bracket level
					squareBracketLevel--;
					//End in case that this was the square bracket which ends the sequence
					if (squareBracketLevel==0){
						c++;
						return result;
					}
				}
				//Next char
				c++;
			}
		}else{
			//No, not starting with '['! This is a simple sequence!
			return parseSequence()[1];
		}
	}