public MathParserTermResult Parse(string expression, int startPos)
{
var i = startPos;
var termType = TermType.Const;
int numberOfParams = 0;
MathParserTermResult internalTermResult = null;
while (i < expression.Length && Char.IsLetter(expression[i]))
{
i++;
}
if (i < expression.Length && expression[i] == '(')
{
var subParser = new SubExpressionTermParser(true);
internalTermResult = subParser.Parse(expression, i);
numberOfParams = subParser.NumberOfParameters;
termType = TermType.Function;
}
var term = expression.Substring(startPos, i - startPos);
var result = new ComplexMathParserResult
{
StartPos = startPos,
EndPos = internalTermResult != null ? internalTermResult.EndPos : i,
Term = term,
TermType = termType,
InternalTerm = internalTermResult,
NumberOfParams = numberOfParams
};
return(result);
}
public MathParserTermResult Parse(string expression, int startPos)
{
var i = startPos;
var openedParenthesis = 0;
if (expression[i] == '(')
{
i++;
while (i < expression.Length)
{
if (expression[i] == '(')
{
openedParenthesis++;
}
else
if (expression[i] == ')')
{
if (openedParenthesis > 0)
{
openedParenthesis--;
}
else
{
break;
}
}
if (_isFunctionExpression && expression[i] == ',' && openedParenthesis == 0)
{
NumberOfParameters++;
}
i++;
}
if (openedParenthesis > 0)
{
throw new InvalidOperationException("No matching ')'!");
}
if (i == expression.Length || expression[i] != ')')
{
throw new InvalidOperationException("Expression should be ended with ')'!");
}
}
if (startPos + 1 == i)
{
throw new InvalidOperationException($"Subexpression is empty!");
}
var result = new ComplexMathParserResult
{
StartPos = startPos + 1,
EndPos = i + 1,
Term = expression.Substring(startPos + 1, i - startPos - 1),
TermType = TermType.Expression
};
return(result);
}