public abstract class ParseTree : Located, IParseTree
{
  public virtual IsAmbiguous    : bool;
  public virtual IsMissing      : bool;
  public virtual RuleDescriptor : RuleDescriptor;

  public virtual Apply(visitor : ParseTreeVisitor) : ParseTree;

  public override ToString() : string;
  public ToString(options : PrettyPrintOptions) : string;
  public ToString(options : PrettyPrintOptions, spans : out List[SpanInfo]) : string;

  public virtual PrettyPrint(writer : PrettyPrintWriter, callerBindingPower : int, spanClass : SpanClass) : void;

  protected virtual PrettyPrintSource : IPrettyPrintSource { get; }

  protected virtual GetSourceSnapshotProvider() : ISourceSnapshotProvider;

  protected virtual GetLocationSpan() : NSpan;
}