/*
* Pushes the current operator token to the stack and pops Evaluatables from the stack
*/
private void FoundOperator(string token, List <string> result)
{
var op = Evaluatables[token];
if (Hold.Count != 0)
{
while (Hold.Count != 0)
{
var topOfStack = Hold.Peek();
if (!Evaluatables.OperatorExists(topOfStack))
{
break;
}
var operatorTop = Evaluatables[topOfStack];
if ((OperatorHelper.CheckAssociativity(op, Associativity.L) && op.Precedence <= operatorTop.Precedence) ||
OperatorHelper.CheckAssociativity(op, Associativity.R) && op.Precedence < operatorTop.Precedence)
{
result.Add(Hold.Pop());
}
else
{
break;
}
}
}
Hold.Push(token);
}
private void FoundSpecialChar(char partialToken, List <string> result)
{
switch (partialToken)
{
case '(':
Hold.Push(partialToken.ToString());
return;
case ')':
/*
* Pop Evaluatables from the stack until a matching parenthesis is found
*/
var foundLeftParenthesis = false;
do
{
var topOfStack = Hold.Pop();
if (topOfStack == "(")
{
foundLeftParenthesis = true;
break;
}
result.Add(topOfStack);
} while (Hold.Count != 0);
if (!foundLeftParenthesis)
{
throw new MissMatchedParenthesisException();
}
break;
case ',':
var topOfstack = Hold.Peek();
while (topOfstack != "(")
{
if (Hold.Count != 0)
{
result.Add(Hold.Pop());
topOfstack = Hold.Peek();
}
else
{
throw new MissMatchedParenthesisException();
}
}
break;
default:
throw new UnexpectedOperatorException($"Unexpected Operator {partialToken}");
}
}
private List <string> InternalConvert(string input)
{
var result = new List <string>();
var inputQueue = new Queue <char>(input.ToCharArray());
do
{
var partialToken = inputQueue.Dequeue(); //Get the next in line to be parsed
var numberToken = CheckIfNumber(partialToken, inputQueue); //Checks if number, empty string if not
if (numberToken != "")
{
QueueHelper.RemoveFromQueue(numberToken.Length - 1, inputQueue); //Remove the items that have already been parsed from the input queue
result.Add(numberToken);
}
else
{
//Checks for operator, returns a stack of possible Evaluatables, the top member of the token stack will be the one used
var operatorTokens = CheckIfOperator(partialToken, inputQueue);
if (operatorTokens.Count != 0)
{
var operatorToken = operatorTokens.Pop();
QueueHelper.RemoveFromQueue(operatorToken.Length - 1, inputQueue);
FoundOperator(operatorToken, result); //Push and pop Evaluatables from the holding stack
}
else
{
FoundSpecialChar(partialToken, result); //If it doesn't find an operator it's most likely a parenthesis
}
}
} while (inputQueue.Count != 0);
while (Hold.Count != 0) //Pop the remaining Evaluatables to the output list
{
var item = Hold.Pop();
if (!Evaluatables.OperatorExists(item))
{
throw new MissMatchedParenthesisException();
}
result.Add(item);
}
return(result);
}
