static IEnumerable <TupBase> While(CommonHeading heading, IEnumerable <TupBase> body, Func <RelNode, RelNode> func)
{
var stack = new Stack <TupBase>(body);
var hash = new HashSet <TupBase>();
while (stack.Count > 0)
{
var top = stack.Pop();
if (!hash.Contains(top))
{
hash.Add(top);
var result = func(new WrapperNode(heading, Enumerable.Repeat(top, 1)));
var eq = result.Heading.IsEqual(heading);
var map = heading.CreateMap(result.Heading);
if (result.Heading.Degree != heading.Degree ||
map.Any(x => x < 0))
{
throw Error.Fatal("While", $"heading mismatch: {result.Heading} {heading}");
}
// convert compatible if needed
foreach (var t in result)
{
stack.Push(eq ? t : RelStatic.CreateByMap <Tup>(t, map));
}
}
}
return(hash);
}
public RenameNode(RelNode source, CommonHeading nodeheading)
{
_source = source;
_nodeheading = nodeheading;
_map = _nodeheading.CreateMap(_source.Heading);
if (!(_map.Length == 2 && _map[0] >= 0 && _map[1] < 0))
{
throw Error.Fatal("Rename", "heading is invalid");
}
Heading = _source.Heading.Rename(_nodeheading[0], _nodeheading[1]);
}
public RestrictNode(RelNode source, CommonHeading nodeheading, RelFuncBase func)
{
_source = source;
_restheading = nodeheading;
_restfunc = func;
Heading = _source.Heading;
_restmap = _restheading.CreateMap(Heading);
if (_restmap.Any(x => x < 0))
{
throw Error.Fatal("Restrict", "heading has unknown attribute");
}
}
public AggregateNode(RelNode source, CommonHeading nodeheading, RelFuncBase func, object initial = null)
{
_source = source;
_heading = nodeheading;
_func = func;
_initial = initial;
Heading = _source.Heading.Rename(_heading[0], _heading[1]);
_vmap = _heading.CreateMap(_source.Heading);
_jhead = _source.Heading.Minus(_heading);
_jmap1 = _jhead.CreateMap(_source.Heading);
_jmap2 = Heading.CreateMap(_jhead);
if (!(_heading.Degree == 2 && _jmap2.Length == Heading.Degree))
{
throw Error.Fatal("Aggregate", "heading is not valid");
}
}
public UngroupNode(RelNode source, UngroupingOp op, CommonHeading nodeheading)
{
_source = source;
_op = op;
_nodeheading = nodeheading;
_nodemap = _nodeheading.CreateMap(_source.Heading);
if (!(_nodemap.Length == 1 && _nodemap[0] >= 0))
{
throw Error.Fatal("Ungroup", "heading is not valid");
}
// on output replace one field by the TVA/RVA
Heading = _source.Heading.Remove(_nodeheading[0]).Append(_nodeheading[0].Fields);
//
var tupheading = CommonHeading.Create(_nodeheading[0].Fields);
_map1 = Heading.CreateMap(_source.Heading);
_map2 = Heading.CreateMap(tupheading);
}
public ExtendNode(RelNode source, CommonHeading nodeheading, RelFuncBase func)
{
_source = source;
_nodeheading = nodeheading;
_func = func;
Heading = CommonHeading.Create(_source.Heading.Fields.Union(_nodeheading.Fields));
// get the argument fields
_argheading = CommonHeading.Create(_nodeheading.Fields.Take(_nodeheading.Fields.Length - 1));
_argmap = _argheading.CreateMap(_source.Heading);
// last field can extend or replace, remove name but retain place
var outh = Heading.Rename(_nodeheading.Fields.Last(), CommonField.Empty);
_outmap = Heading.CreateMap(outh);
if (_argmap.Any(x => x < 0))
{
throw Error.Fatal("Extend", "heading has unknown attribute");
}
if (_outmap.Count(x => x < 0) != 1)
{
throw Error.Fatal("Extend", "invalid heading, invalid new attribute"); // any use?
}
}