public IEnumerable <Token> Tokenize(TextReader reader)
{
var token = new StringBuilder();
int curr;
while ((curr = reader.Read()) != -1)
{
var ch = (char)curr;
var currType = DetermineType(ch);
if (currType == TokenType.WhiteSpace)
{
continue;
}
if (currType == TokenType.Exeption)
{
ShuntingYardException ShuntingYardExeption = new ShuntingYardException("Wrong symbol", ch);
continue;
}
token.Append(ch);
var next = reader.Peek();
var nextType = next != -1 ? DetermineType((char)next) : TokenType.WhiteSpace;
if (currType != nextType)
{
if (next == '(')
{
yield return(new Token(TokenType.Function, token.ToString()));
}
else
{
yield return(new Token(currType, token.ToString()));
}
token.Clear();
}
}
}
public IEnumerable <Token> ShuntingYard(IEnumerable <Token> tokens)
{
var stack = new Stack <Token>();
foreach (var tok in tokens)
{
switch (tok.Type)
{
case TokenType.Polynomial:
case TokenType.Variable:
yield return(tok);
break;
case TokenType.Function:
stack.Push(tok);
break;
case TokenType.Comma:
while (stack.Peek().Value != "(")
{
yield return(stack.Pop());
}
break;
case TokenType.Operator:
while (stack.Any() && stack.Peek().Type == TokenType.Operator && CompareOperators(tok.Value, stack.Peek().Value))
{
yield return(stack.Pop());
}
stack.Push(tok);
break;
case TokenType.Parenthesis:
if (tok.Value == "(")
{
stack.Push(tok);
}
else
{
if (stack.Count != 0)
{
while (stack.Peek().Value != "(")
{
yield return(stack.Pop());
}
stack.Pop();
if (stack.Peek().Type == TokenType.Function)
{
yield return(stack.Pop());
}
}
}
break;
default:
ShuntingYardException ShuntingYardExeption = new ShuntingYardException("Wrong token", tok);
break;
}
}
while (stack.Any())
{
var tok = stack.Pop();
if (tok.Type == TokenType.Parenthesis)
{
ShuntingYardException ShuntingYardExeption = new ShuntingYardException("Mismatched parentheses");
continue;
}
yield return(tok);
}
}
