@Override
	public Result<T> eval(final Tree<? extends Op<T>, ?> program) {
		requireNonNull(program);

		final SampleList<T> snapshot = _snapshot;
		return snapshot != null && !snapshot.isEmpty()
			? snapshot.eval(program)
			: null;
	}
Return the currently <em>published</em> sample points.

@see #publish()

@return the currently <em>published</em> sample points
jenetics.prog/src/main/java/io/jenetics/prog/regression/SampleBuffer.java