case PROCESS:
Controller controller = context.getController();
XPathContext c2 = context.newMinorContext();
c2.setOrigin(exp);
SequenceOutputter seq = controller.allocateSequenceOutputter(20);
PipelineConfiguration pipe = controller.makePipelineConfiguration();
pipe.setHostLanguage(exp.getHostLanguage());
seq.setPipelineConfiguration(pipe);
c2.setTemporaryReceiver(seq);
seq.open();
exp.process(c2);
seq.close();
ValueRepresentation val = seq.getSequence();
seq.reset();
return val;
case LAZY_TAIL_EXPRESSION: {
TailExpression tail = (TailExpression)exp;
VariableReference vr = (VariableReference)tail.getBaseExpression();