public override IEnumerable <ResultTree> Run()
{
if (this.Value.Any())
{
var head = this.Value.First().Run();
var tail = new GroupExpression(this.Value.Skip(1)).Run();
return(head.SelectMany(child => concat(child, tail)));
}
else
{
return(EnumerableExt.Yield <ResultTree>(null));
}
static IEnumerable <ResultTree> concat(ResultTree head, IEnumerable <ResultTree> tail)
{
if (head is null)
{
return(tail);
}
else if (head is StructureResultTree c)
{
return(EnumerableExt.Yield(new StructureResultTree(c.Name,
c.FirstChild,
c.NextSibling.SelectMany(x => concat(x, tail)))));
}
else
{
throw new NotImplementedException();
}
}
public override IEnumerable <ResultTree> Run()
{
yield return(new StructureResultTree(this.Name, this.Value.Run(), EnumerableExt.Yield <ResultTree>(null)));
}