public void WhenWrongOperatorExpressionIsPassed_Then_ExceptionShouldBeThrown()
{
var sut = new OperatorTermParser();
Assert.Throws <InvalidOperationException>(() =>
{
var result = sut.Parse("&", 0);
});
}
public void WhenExpressionIsPassed_Then_ItShoulBeOperator(string expression)
{
var sut = new OperatorTermParser();
var result = sut.Parse(expression, 0);
Assert.True(result.TermType == TermType.Operator);
Assert.True(result.Term == expression);
}
public List <MathParserTermResult> Parse(string expression, bool allowParameters = false)
{
var terms = new List <MathParserTermResult>();
if (String.IsNullOrWhiteSpace(expression))
{
throw new ArgumentNullException("Expression cannot be empty!");
}
var i = 0;
while (i < expression.Length)
{
MathParserTermResult term = null;
if (Char.IsDigit(expression[i]))
{
term = new NumberTermParser().Parse(expression, i);
}
else
if (OperatorTermParser.IsOperator(expression[i]))
{
term = new OperatorTermParser().Parse(expression, i);
}
else
if (Char.IsLetter(expression[i]))
{
term = new FunctionOrConstTermParser().Parse(expression, i);
}
else
if (SubExpressionTermParser.IsOpenParenthesis(expression[i]))
{
term = new SubExpressionTermParser().Parse(expression, i);
}
else
if (allowParameters && expression[i] == ',')
{
i++;
continue;
}
if (term != null)
{
i = term.EndPos;
terms.Add(term);
}
else
{
throw new InvalidOperationException($"Wrong character '{expression[i]}' at [{i}]!");
}
}
return(terms);
}
