//http://pl.wikipedia.org/wiki/Odwrotna_notacja_polska#Algorytm_obliczenia_warto.C5.9Bci_wyra.C5.BCenia_ONP
private variable CalulateRPNStatement(List<Token> tokensInRPN, IDictionary<string, variable> localVariables, IDictionary<string, variable> inheritedVariables)
{
Stack<Token> stack = new Stack<Token>();
foreach (Token token in tokensInRPN)
{
if (token.GetType() == typeof(variable))
{
stack.Push(token);
}
else if (token.GetType() == typeof(LeftSideOper) || token.GetType() == typeof(RightSideOper))
{
if (stack.Count < ((Oper)token).noOfArguments)
throw new ApplicationException("no of needed arguments is bigger than no of tokens on stack");
variable[] parameters = new variable[((Oper)token).noOfArguments];
for (int i = 0; i < ((Oper)token).noOfArguments; i++)
{
if(stack.Peek().GetType() != typeof(variable))
throw new ApplicationException("wrong no of arguments in stack");
parameters[i] = (variable)stack.Pop();
}
stack.Push(((Oper)token).Execute(parameters));
}
else if (token.GetType() == typeof(Function))
{
if (stack.Count < ((Function)token).agrumgensNo)
throw new ApplicationException("no of needed arguments is bigger than no of tokens on stack");
variable[] arguments = new variable[((Function)token).agrumgensNo];
for (int i = 0; i < ((Function)token).agrumgensNo; i++)
{
if (stack.Peek().GetType() != typeof(Function))
throw new ApplicationException("wrong no of arguments in stack");
arguments[i] = (variable)stack.Pop();
}
stack.Push(((Function)token).Execute(arguments));
}
else
{
throw new ApplicationException("unhandled token");
}
}
if (stack.Count != 1)
throw new ApplicationException("there should be only 1 value on stack");
if (stack.Peek().GetType() != typeof(variable))
throw new ApplicationException("last token on stack should be a variable");
return (variable)stack.Pop();
}
public override variable Execute(variable[] arguments)
{
switch (code)
{
case "+":
return new variable(arguments[1].value + arguments[0].value);
case "*":
return new variable(arguments[1].value * arguments[0].value);
default:
throw new ApplicationException("unresolved operator");
}
}
public abstract variable Execute(variable[] arguments);
public override variable Execute(variable[] arguments)
{
throw new ApplicationException("you cannot execute bracket!");
}
public override variable Execute(variable[] arguments)
{
switch (code)
{
case "=":
arguments[1].value = arguments[0].value;
return arguments[1];
default:
throw new ApplicationException("unresolved operator");
}
}
public variable Execute(variable[] arguments)
{
throw new NotImplementedException();
}