@Override
	public String toString() {
		StringBuilder s = new StringBuilder();
		s.append(this.expressionString).append("\n");
		for (int i = 0; i < this.pos; i++) {
			s.append(" ");
		}
		s.append("^\n");
		s.append(tokens).append("\n");
		return s.toString();
	}
Push a token of two characters in length.
spring-xd-dirt/src/main/java/org/springframework/xd/dirt/stream/dsl/Tokenizer.java