private int startPos(Iterable<Token> many) {
		Iterator<Token> iterator = many.iterator();
		Assert.isTrue(iterator.hasNext(), "list of tokens must not be empty");
		return iterator.next().startpos;
	}
Return the startPos of the first token in the list (must be non empty).
spring-xd-dirt/src/main/java/org/springframework/xd/dirt/stream/dsl/StreamConfigParser.java