/// <summary>
/// Парсинг математического выражения
/// </summary>
/// <param name="mathExpression"></param>
/// <param name="variables"></param>
/// <returns>MathTryParseResult</returns>
public MathTryParseResult TryParse(string mathExpression, ICollection <Variable> variables = null)
{
var defaultResult = new MathTryParseResult()
{
IsSuccessfulCreated = false,
InputString = mathExpression
};
var parameters = new MathParserTryParseParameters(mathExpression, variables);
var errorMessage = CheckTryParseParameters(parameters);
if (!string.IsNullOrEmpty(errorMessage))
{
defaultResult = defaultResult with {
ErrorMessage = errorMessage
};
return(defaultResult);
}
var tryParseResult = TryParseExpression(parameters.MathExpression, parameters.Variables);
tryParseResult = tryParseResult with {
InputString = defaultResult.InputString
};
return(tryParseResult);
}
private string CheckTryParseParameters(MathParserTryParseParameters parameters)
{
var errorMessage = "";
var mathExpression = parameters.MathExpression;
var variables = parameters.Variables;
if (string.IsNullOrEmpty(mathExpression) || mathExpression.All(ch => char.IsWhiteSpace(ch)))
{
errorMessage = $"Empty string in mathExpression";
}
//проверка на корректность имен переменных
if (variables != null && variables.Any(v => string.IsNullOrEmpty(v.Name)))
{
errorMessage = $"Empty variable name";
}
if (variables != null && variables.Any(v => v.Name.Any(ch => !char.IsLetter(ch))))
{
errorMessage = $"Incorrect variable name";
}
//проверка имен переменных на совпадение с именами констант
var matchedName = string.Empty;
if (variables != null)
{
matchedName = variables.Where(v => _mathparserEntities.Exists(c => c.Name.ToString() == v.Name.ToLower()))
.Select(v => v.Name)
.FirstOrDefault();
}
if (!string.IsNullOrEmpty(matchedName))
{
errorMessage = $"Wrong name for variable {matchedName}. There is already entity with the same name";
}
//форматирование строки
mathExpression = mathExpression.Replace(" ", "");
mathExpression = mathExpression.ToLower();
if (!Validate.IsBracketsAreBalanced(mathExpression))
{
errorMessage = "brackets are not balanced";
}
while (Validate.IsExpressionInBrackets(mathExpression))
{
mathExpression = mathExpression
.Remove(mathExpression.Length - 1, 1)
.Remove(0, 1);
}
parameters.MathExpression = mathExpression;
if (string.IsNullOrEmpty(mathExpression))
{
errorMessage = $"Empty string in mathExpression";
}
return(errorMessage);
}
