private int DoMove(int predictedMove, int i, ref Buffer buffer)
{
string lbl = ""; // Data.Index2Label[predictedMove];
switch (predictedMove)
{
case LEFT: { buffer.AddArc(i, buffer.Stack.Pop(), lbl); return(i); }
case RIGHT: { int child = buffer.Stack.Pop(); buffer.AddArc(buffer.Stack[0], child, lbl); return(i); }
case SHIFT: { buffer.Stack.Push(i); return(i + 1); }
}
throw new Exception("Invalid move: " + predictedMove);
}