// Middle-ware function
private static void CreateExpr(Opr operation, ref Stack <Expression> exprStack)
{
Expression ex2 = exprStack.Pop();
Expression ex1;
switch (operation.Show())
{
case "x":
ex1 = exprStack.Pop();
exprStack.Push(new MultExpression(ex1, ex2)); break;
case "+":
ex1 = exprStack.Pop();
exprStack.Push(new AddExpression(ex1, ex2)); break;
case "^":
ex1 = exprStack.Pop();
exprStack.Push(new PowerExpression(ex1, ex2)); break;
case "÷":
ex1 = exprStack.Pop();
exprStack.Push(new DivExpression(ex1, ex2)); break;
case "-":
ex1 = exprStack.Pop();
exprStack.Push(new MinusExpression(ex1, ex2)); break;
case "√":
exprStack.Push(new RootExpression(ex2)); break;
case ";":
exprStack.Push(new NegativeExpression(ex2)); break;
default:
throw new SyntaxErrorException();
}
}
private static void PrintEvaluationState(Opr opr, Expression expr1, Expression expr2)
{
Console.Write("Operation State: ");
Console.WriteLine(expr1.Solve() + opr.Show() + expr2.Solve());
}
public Expression Evaluate()
{
string[] tokenList = parser.GetParseResult();
Stack <Expression> exprStack = new Stack <Expression>();
Stack <Opr> oprStack = new Stack <Opr>();
double numHolder;
Opr oprHolder;
foreach (string token in tokenList)
{
if (Parser.CheckOperand(token))
{
CheckStateOperand();
numHolder = Double.Parse(token);
exprStack.Push(new TerminalExpression(numHolder));
ChangeState();
}
else if (Parser.CheckUnaryOperator(token))
{
CheckStateOperand();
oprStack.Push(CreateOpr(token));
}
else if (Parser.CheckBinaryOperator(token))
{
CheckStateOperator();
oprHolder = CreateOpr(token);
while (oprStack.Count != 0 && oprHolder.GetOprPred() <= oprStack.Peek().GetOprPred())
{
Opr outOpr = oprStack.Pop();
CreateExpr(outOpr, ref exprStack);
}
oprStack.Push(oprHolder);
ChangeState();
}
else if (Parser.CheckParentheses(token))
{
switch (token)
{
case "(":
CheckStateOperand();
oprStack.Push(CreateOpr(token));
break;
case ")":
CheckStateOperator();
while (oprStack.Count != 0 && oprStack.Peek().Show() != "(")
{
oprHolder = oprStack.Pop();
CreateExpr(oprHolder, ref exprStack);
}
if (oprStack.Count == 0)
{
throw new ParenthesesErrorException();
}
if (oprStack.Peek().Show() == "(")
{
oprStack.Pop();
}
break;
}
}
else //Token tidak terdefinisi
{
throw new UndefinedToken(token);
}
}
CheckStateOperator();
// Finishing Evaluation Process
while (oprStack.Count != 0 && exprStack.Count != 0)
{
oprHolder = oprStack.Pop();
CreateExpr(oprHolder, ref exprStack);
}
if (oprStack.Count > 0 || exprStack.Count > 1) // Syntax error
{
throw new SyntaxErrorException();
}
return(exprStack.Pop());
}
// Debugging function
private static void PrintOperatorState(Opr opr, string state)
{
Console.WriteLine(state + ":");
Console.WriteLine("Operator:" + opr.Show());
}