public ParserResult Evaluate(IParserContext input)
{
Stack <SyntaxToken> stack = new Stack <SyntaxToken>();
foreach (LexicToken lt in input.Stream)
{
if (lt is ConstantLexicToken)
{
ConstantLexicToken clt = (ConstantLexicToken)lt;
SyntaxToken st = SyntaxToken.Constant(double.Parse(clt.Value, CultureInfo.InvariantCulture));
stack.Push(st);
}
else if (lt is VariableLexicToken)
{
VariableLexicToken vlt = (VariableLexicToken)lt;
SyntaxToken st = SyntaxToken.Variable(vlt.Name);
if (Parser.IsPI(vlt.Name))
{
st = SyntaxToken.PI;
}
else if (Parser.IsE(vlt.Name))
{
st = SyntaxToken.E;
}
stack.Push(st);
}
else if (lt is OperatorLexicToken)
{
if (lt is FactorialLexicToken)
{
stack.Push(SyntaxToken.Factorial(stack.Pop()));
continue;
}
SyntaxToken right = stack.Pop();
SyntaxToken left = stack.Pop();
stack.Push(this.GetOperatorFunction((OperatorLexicToken)lt)(left, right));
}
else if (lt is FunctionLexicToken)
{
FunctionType function = input.GetFunction(((FunctionLexicToken)lt).Name);
switch (function)
{
case FunctionType.Sin:
stack.Push(SyntaxToken.Sin(stack.Pop()));
break;
case FunctionType.Cos:
stack.Push(SyntaxToken.Cos(stack.Pop()));
break;
case FunctionType.Tan:
stack.Push(SyntaxToken.Tan(stack.Pop()));
break;
case FunctionType.Cot:
stack.Push(SyntaxToken.Cot(stack.Pop()));
break;
case FunctionType.Asin:
stack.Push(SyntaxToken.Asin(stack.Pop()));
break;
case FunctionType.Acos:
stack.Push(SyntaxToken.Acos(stack.Pop()));
break;
case FunctionType.Atan:
stack.Push(SyntaxToken.Atan(stack.Pop()));
break;
case FunctionType.Acot:
stack.Push(SyntaxToken.Acot(stack.Pop()));
break;
case FunctionType.Log:
SyntaxToken right = stack.Pop();
SyntaxToken left = stack.Pop();
stack.Push(SyntaxToken.Log(left, right));
break;
case FunctionType.Ln:
stack.Push(SyntaxToken.Ln(stack.Pop()));
break;
case FunctionType.Abs:
stack.Push(SyntaxToken.Abs(stack.Pop()));
break;
case FunctionType.Unsupported:
default: throw new NotSupportedException();
}
}
else
{
throw new NotSupportedException();
}
}
ParserResult result = new ParserResult(stack.Pop());
if (stack.Any())
{
throw new InvalidOperationException("There are still values in the queue.");
}
return(result);
}