private void revert(Node currentNode, Node leftChild, Token leftToken)
{
currentNode.LeftChild = leftChild.LeftChild;
var rightChild = currentNode.RightChild;
rightChild.Token.Id = IdGenerator.GetIdGenerator();
var node = new Node
{
Token = (Token)leftToken.Clone(),
LeftChild = leftChild.RightChild,
RightChild = RightChild
};
node.Token.Id = IdGenerator.GetIdGenerator();
currentNode.RightChild = node;
}
private bool optimize()
{
if (LeftChild != null &&
LeftChild.Depth > RightChild.Depth + 1)
{
if (Token is PlusToken || Token is MultiplyToken)
{
reduce(this, LeftChild);
return(true);
}
if (LeftChild.Token is DivideToken)
{
revert(this, LeftChild, new MultiplyToken(IdGenerator.GetIdGenerator()));
return(true);
}
if (LeftChild.Token is MinusToken)
{
revert(this, LeftChild, new MultiplyToken(IdGenerator.GetIdGenerator()));
return(true);
}
}
return(false);
}
public IEnumerable <Token> Scan(string expression)
{
_reader = new StringReader(expression);
try
{
var tokens = new List <Token>();
while (_reader.Peek() != -1)
{
var c = (char)_reader.Peek();
if (Char.IsWhiteSpace(c))
{
_reader.Read();
continue;
}
if (Char.IsDigit(c) || c == '.')
{
var nr = ParseNumber();
tokens.Add(new NumberConstantToken(nr));
}
else if (c == '-')
{
tokens.Add(new MinusToken(IdGenerator.GetIdGenerator()));
_reader.Read();
}
else if (c == '+')
{
tokens.Add(new PlusToken(IdGenerator.GetIdGenerator()));
_reader.Read();
}
else if (c == '*')
{
tokens.Add(new MultiplyToken(IdGenerator.GetIdGenerator()));
_reader.Read();
}
else if (c == '/')
{
tokens.Add(new DivideToken(IdGenerator.GetIdGenerator()));
_reader.Read();
}
else if (c == '(')
{
tokens.Add(new OpenParenthesisToken(IdGenerator.GetIdGenerator()));
_reader.Read();
}
else if (c == ')')
{
tokens.Add(new ClosedParenthesisToken(IdGenerator.GetIdGenerator()));
_reader.Read();
}
else if (char.IsLetter(c))
{
var variable = ParseVariable();
tokens.Add(new NumberConstantToken(variable));
}
else
{
throw new Exception("Unknown character in expression: " + c);
}
}
return(tokens);
}
catch (Exception e)
{
Console.Write(e.Message);
Console.ReadLine();
return(new List <Token>());
}
}
public override object Clone()
{
return(new MultiplyToken(IdGenerator.GetIdGenerator()));
}
public override object Clone()
{
return(new PlusToken(IdGenerator.GetIdGenerator()));
}
public override object Clone()
{
return(new ClosedParenthesisToken(IdGenerator.GetIdGenerator()));
}