public void Sort(QilNode sortKeys)
{
if (sortKeys != null)
{
// If sorting is required, cache the input node-set to support last() within sort key expressions
EnsureCache();
// The rest of the loop content must be compiled in the context of already sorted node-set
_current = _f.For(_f.Sort(_current, sortKeys));
}
}
// Filers that travers Content being converted to global travers:
// Filter($j= ... Filter($i = Content(fixup), ...)) -> Filter($j= ... Filter($i = Loop($j = DesendentOrSelf(Root(fixup)), Content($j), ...)))
protected override QilNode VisitLoop(QilLoop n)
{
if (n.Variable.Binding.NodeType == QilNodeType.Root || n.Variable.Binding.NodeType == QilNodeType.Deref)
{
// This is absolute path already. We shouldn't touch it
return(n);
}
if (n.Variable.Binding.NodeType == QilNodeType.Content)
{
// This is "begin" of reletive path. Let's rewrite it as absolute:
QilUnary content = (QilUnary)n.Variable.Binding;
Debug.Assert(content.Child == this.fixup, "Unexpected content node");
QilIterator it = f.For(f.DescendantOrSelf(f.Root(this.fixup)));
content.Child = it;
n.Variable.Binding = f.Loop(it, content);
return(n);
}
n.Variable.Binding = Visit(n.Variable.Binding);
return(n);
}