//also used by XPathPatternBuilder
public static QilNode PredicateToBoolean(QilNode predicate, XPathQilFactory f, IXPathEnvironment env)
{
// Prepocess predicate: if (predicate is number) then predicate := (position() == predicate)
if (!f.IsAnyType(predicate))
{
if (predicate.XmlType.TypeCode == XmlTypeCode.Double)
{
predicate = f.Eq(env.GetPosition(), predicate);
}
else
{
predicate = f.ConvertToBoolean(predicate);
}
}
else
{
QilIterator i;
predicate = f.Loop(i = f.Let(predicate),
f.Conditional(f.IsType(i, T.Double),
f.Eq(env.GetPosition(), f.TypeAssert(i, T.DoubleX)),
f.ConvertToBoolean(i)
)
);
}
return(predicate);
}
protected override QilNode VisitUnknown(QilNode unknown)
{
Debug.Assert(unknown.NodeType == QilNodeType.Unknown);
if (unknown == _fixupCurrent)
{
numCurrent++;
if (!_justCount)
{
if (_environment != null)
{
unknown = _environment.GetCurrent();
}
else if (_current != null)
{
unknown = _current;
}
}
}
else if (unknown == _fixupPosition)
{
numPosition++;
if (!_justCount)
{
if (_environment != null)
{
unknown = _environment.GetPosition();
}
else if (_current != null)
{
// position can be in predicate only and in predicate current olways an iterator
unknown = f.XsltConvert(f.PositionOf((QilIterator)_current), T.DoubleX);
}
}
}
else if (unknown == _fixupLast)
{
numLast++;
if (!_justCount)
{
if (_environment != null)
{
unknown = _environment.GetLast();
}
else if (_current != null)
{
Debug.Assert(_last != null);
unknown = _last;
}
}
}
Debug.Assert(unknown != null);
return(unknown);
}