Sequence seq = getArgument(0).eval(docs, contextSequence);
Sequence seq = getArgument(0).eval(contextSequence);
	public Sequence eval(DocumentSet docs, Sequence contextSequence, Item contextItem)		throws XPathException {		if(contextItem != null)			contextSequence = contextItem.toSequence();		Sequence seq = getArgument(0).eval(docs, contextSequence);		if(seq.getLength() == 0)			return Sequence.EMPTY_SEQUENCE;		String value = seq.getStringValue();		return new StringValue(value.toUpperCase());	}