/// <summary>
/// Push element to the top of the stack
/// </summary>
/// <param name="newString">content</param>
public void Push(string newString)
{
lock (_lock)
{
// First create new StackString object and save it to DB to get a new ID
var stackString = new StackString(newString);
var record = _db.StackStrings.Add(stackString);
_db.SaveChanges();
// Connect it via 2way binding to the top element of the stack according to the order
if (_stackDirection == StackDirection.IN_ORDER)
{
var left = _db.StackStrings
.SingleOrDefault(s => s.LeftId == StackString.LEFT_ID);
if (left != null)
{
left.LeftId = stackString.StackStringId;
stackString.RightId = left.StackStringId;
stackString.LeftId = StackString.LEFT_ID;
}
}
else
{
var right = _db.StackStrings
.SingleOrDefault(s => s.RightId == StackString.RIGHT_ID);
if (right != null)
{
right.RightId = stackString.StackStringId;
stackString.LeftId = right.StackStringId;
stackString.RightId = StackString.RIGHT_ID;
}
}
// If one of the sides is not connected - this is the first element
if (stackString.LeftId == StackString.INVALID_ID ||
stackString.RightId == StackString.INVALID_ID)
{
stackString.LeftId = StackString.LEFT_ID;
stackString.RightId = StackString.RIGHT_ID;
}
_db.SaveChanges();
}
}
public Token[] Tokenize(string str)
{
_symbolsStack = new StackString(str);
var tokens = new List <Token>();
while (_symbolsStack.TryPeek(out var ch))
{
if (char.IsWhiteSpace(ch))
{
_symbolsStack.Pop();
continue;
}
tokens.Add(ReadToken());
}
_symbolsStack = null;
return(tokens.ToArray());
}
