/// <summary>
/// Consists of a collection of expressions in brackets (if there are in the string) and a list of summands (contained between brackets, if any).
/// If there are no brackets, then the monomial consists of one summand)
/// </summary>
/// <param name="monomialString"></param>
/// <returns></returns>
public static Monomial Parse(string monomialString)
{
if (monomialString == null)
{
throw new ArgumentNullException(nameof(monomialString));
}
if (monomialString.IsNullOrWhiteSpace())
{
throw new ArgumentException(nameof(monomialString));
}
var summandItems = ParseHelper.GetSummandsForMonomial(monomialString);
//default value:
//for brackets - 1 '(x-1) -> 1(x-1)'
//otherwise - 0 'x^0 + a -> 1+a'
var summand = summandItems.summandItems.Select(SummandParser.Parse).Multiply()
?? new Summand(summandItems.bracketsParts.Count > 0 ? 1 : 0);
IEnumerable <Summand> resultSummands = summand != null ? new [] { summand } : new Summand[] { };
IEnumerable <Summand> result = resultSummands;
foreach (var part in summandItems.bracketsParts)
{
var rightItems = PolynomialParser.Parse(part).Normalize().Summands.Sum();
result = EquationOperation.Multiply(result, rightItems);
}
resultSummands = result.Sum();
return(new Monomial(resultSummands ?? new Summand[] {}));
}
public static Equation Parse(string equationString)
{
if (equationString.IsNullOrWhiteSpace())
{
throw new ArgumentNullException(nameof(equationString), "String shouldn't be empty");
}
var transformedEquationString = equationString.RemoveWhiteSpaces();
var equationExpressionsStringParts = transformedEquationString.Split(new[] { '=' }, StringSplitOptions.RemoveEmptyEntries);
if (equationExpressionsStringParts.Length == 0)
{
throw new NotValidEquationArgumentException("Symbol '=' not found in source string");
}
if (equationExpressionsStringParts.Length == 1)
{
throw new NotValidEquationArgumentException("The equation must be filled on either side of the symbol '='");
}
if (equationExpressionsStringParts.Length > 2)
{
throw new NotValidEquationArgumentException("There must be only one symbol '=' in the equation");
}
var leftPart = equationExpressionsStringParts[0];
var rightPart = equationExpressionsStringParts[1];
var left = PolynomialParser.Parse(leftPart);
var right = PolynomialParser.Parse(rightPart);
return(new Equation(left, right));
}
