static Token EvalParenthesis(
Token root)
{
var openingParenthesis = root.FindLast(TokenType.OpeningParenthesis);
while (openingParenthesis != null)
{
var closingParenthesis = openingParenthesis.Find(TokenType.ClosingParenthesis);
if (closingParenthesis == null)
{
throw new EvaluationException("Missing closing parenthesis.");
}
var previous = openingParenthesis.TruncatePrevious();
var next = closingParenthesis.TruncateNext();
openingParenthesis = openingParenthesis.TruncateNext();
closingParenthesis = closingParenthesis.TruncatePrevious();
var token = EvalFunctionsAndOperators(openingParenthesis);
var value = token.As <OperandToken>().Value;
root = new OperandToken(value);
root.ReplacePrevious(previous);
root.ReplaceNext(next);
openingParenthesis = root.Find(TokenType.OpeningParenthesis, true);
}
return(root.FindRoot());
}
