private QilNode MatchPatternsWhosePriorityGreater(QilIterator it, List <Pattern> patternList, QilNode matcher)
{
if (patternList.Count == 0)
{
return(matcher);
}
if (IsNoMatch(matcher))
{
return(MatchPatterns(it, patternList));
}
QilIterator stopPriority = f.Let(matcher);
QilNode result = f.Int32(NoMatch);
int lastPriority = NoMatch;
foreach (Pattern pattern in patternList)
{
// if (stopPriority > pattern.Priority) then stopPriority else
// if ($it =~ pattern.Match) then pattern.Priority else...
// First 'if' is generated lazily since it is not needed if priorities are consecutive numbers
Debug.Assert(pattern.Priority > lastPriority);
if (pattern.Priority > lastPriority + 1)
{
result = f.Conditional(f.Gt(stopPriority, f.Int32(lastPriority)), stopPriority, result);
}
result = f.Conditional(MatchPattern(it, pattern.Match), f.Int32(pattern.Priority), result);
lastPriority = pattern.Priority;
}
// If the last pattern has the highest priority, the check can be eliminated
if (lastPriority != this.priority)
{
result = f.Conditional(f.Gt(stopPriority, f.Int32(lastPriority)), stopPriority, result);
}
return(f.Loop(stopPriority, result));
}
// Filers that travers Content being converted to global travers:
// Filter($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);
}