private Summand CreateSummand(string lexem)
{
float coefficient = 1.0f;
Variable[] variables = null;
using (var lexemEnumerator = new LexemEnumerator(lexem))
{
while (lexemEnumerator.MoveNext())
{
if (lexemEnumerator.Current == Symbol.Minus)
{
coefficient *= -1;
}
if (char.IsDigit(lexemEnumerator.Current))
{
coefficient *= ReadNextFloatDigit(lexemEnumerator);
}
if (lexemEnumerator.IsHasValue && char.IsLetter(lexemEnumerator.Current))
{
variables = ReadVariables(lexemEnumerator);
}
}
}
return(new Summand(variables, coefficient));
}
private Variable[] ReadVariables(LexemEnumerator enumerator)
{
var resultVariables = new List <Variable>();
while (enumerator.IsHasValue)
{
resultVariables.Add(ReadNextVariable(enumerator));
}
return(resultVariables.ToArray());
}
private Variable ReadNextVariable(LexemEnumerator enumerator)
{
var variableLexem = enumerator.Current;
if (enumerator.MoveNext() &&
enumerator.Current == Symbol.DegreeSymbol)
{
enumerator.MoveNext();
var degree = ReadNextIntDigit(enumerator);
return(new Variable(variableLexem, degree));
}
return(new Variable(variableLexem));
}
private int ReadNextIntDigit(LexemEnumerator enumerator)
{
var lexem = enumerator.Current.ToString();
while (enumerator.MoveNext())
{
if (char.IsDigit(enumerator.Current))
{
lexem += enumerator.Current;
}
else
{
break;
}
}
return(int.Parse(lexem));
}
private float ReadNextFloatDigit(LexemEnumerator enumerator)
{
var lexem = enumerator.Current.ToString();
while (enumerator.MoveNext())
{
var ch = enumerator.Current;
if (char.IsDigit(ch) || ch == Symbol.DotSeparator)
{
lexem += ch;
}
else
{
break;
}
}
return(ParseToFloat(lexem));
}