internal void Append(SymbolAndPower symbolAndPower, SymbolFormat symbolFormat)
{
this.Append(symbolAndPower.Symbol);
if (symbolAndPower.Power == 1)
{
return;
}
switch (symbolFormat)
{
case SymbolFormat.SignedHatPowers:
this.Append('^');
this.Append(symbolAndPower.Power.ToString(CultureInfo.InvariantCulture));
break;
case SymbolFormat.FractionHatPowers:
{
var power = Math.Abs(symbolAndPower.Power);
if (power == 1)
{
return;
}
this.Append('^');
this.Append(power.ToString(CultureInfo.InvariantCulture));
break;
}
case SymbolFormat.SignedSuperScript:
{
if (symbolAndPower.Power == 1)
{
return;
}
if (symbolAndPower.Power < 0)
{
this.Append(SuperScript.Minus);
}
this.Append(SuperScript.GetChar(Math.Abs(symbolAndPower.Power)));
break;
}
case SymbolFormat.Default:
case SymbolFormat.FractionSuperScript:
{
var power = Math.Abs(symbolAndPower.Power);
if (power == 1)
{
return;
}
this.Append(SuperScript.GetChar(Math.Abs(symbolAndPower.Power)));
break;
}
default:
throw new ArgumentOutOfRangeException(nameof(symbolFormat), symbolFormat, null);
}
}
internal static bool TryRead(string text, ref int pos, out SymbolAndPower result)
{
if (pos == text.Length)
{
result = default(SymbolAndPower);
return(false);
}
var start = pos;
while (text.Length > pos && IsSymbol(text[pos]))
{
pos++;
}
if (pos == start)
{
result = default(SymbolAndPower);
return(false);
}
var symbol = text.Substring(start, pos - start);
WhiteSpaceReader.TryRead(text, ref pos);
int power;
if (!PowerReader.TryRead(text, ref pos, out power))
{
pos = start;
result = default(SymbolAndPower);
return(false);
}
if (power == 0 || Math.Abs(power) > 5) // 5 > is most likely a typo right?
{
pos = start;
result = default(SymbolAndPower);
return(false);
}
result = new SymbolAndPower(symbol, power);
return(true);
}
internal static bool TryRead(string text, ref int pos, out IReadOnlyList <SymbolAndPower> result)
{
var start = pos;
var sign = Sign.Positive;
List <SymbolAndPower> saps = null;
while (pos < text.Length)
{
WhiteSpaceReader.TryRead(text, ref pos);
if (!TryRead(text, ref pos, out SymbolAndPower sap))
{
pos = start;
result = null;
return(false);
}
if (sap.Power < 0 &&
sign == Sign.Negative)
{
pos = start;
result = null;
return(false);
}
if (sign == Sign.Negative)
{
sap = new SymbolAndPower(sap.Symbol, -1 * sap.Power);
}
if (saps == null)
{
saps = new List <SymbolAndPower>();
}
saps.Add(sap);
var op = OperatorReader.TryReadMultiplyOrDivide(text, ref pos);
if (op != MultiplyOrDivide.None)
{
WhiteSpaceReader.TryRead(text, ref pos);
if (OperatorReader.TryReadMultiplyOrDivide(text, ref pos) != MultiplyOrDivide.None)
{
pos = start;
result = null;
return(false);
}
if (op == MultiplyOrDivide.Division)
{
if (sign == Sign.Negative)
{
pos = start;
result = null;
return(false);
}
sign = Sign.Negative;
}
}
}
if (saps == null || !IsUnique(saps))
{
result = null;
return(false);
}
result = saps;
return(true);
}
