private static TokenType?unsignedNumber(Scanner s)
{
if (!s.isDigit())
{
return(null);
}
while (s.isDigit())
{
s.readChar();
}
if (s.isExponent())
{
return(readExponent(s));
}
if (s.peek() != '.')
{
return(TokenType.Integer);
}
return(remainingFloat(s));
}
private static TokenType?remainingFloat(Scanner s)
{
s.readChar(); // Skip the '.'
while (s.isDigit() || s.isExponent())
{
if (s.isExponent())
{
return(readExponent(s));
}
s.readChar();
}
return(TokenType.Double);
}
private static TokenType?readExponent(Scanner s)
{
s.readChar(); // Skip exponent market
var read = false;
if (s.isOneOf("+-"))
{
s.readChar();
read = true;
}
while (s.isDigit())
{
read = true;
s.readChar();
}
if (read)
{
return(TokenType.Double);
}
// It's not a floating point number in exponent format.
// Read it as a symbol instead.
matchSymbol(s);
return(TokenType.Symbol);
}
private static TokenType? unsignedNumber(Scanner s)
{
if (!s.isDigit())
return null;
while (s.isDigit())
s.readChar();
if (s.isExponent())
return readExponent(s);
if (s.peek() != '.')
return TokenType.Integer;
return remainingFloat(s);
}
private static TokenType? remainingFloat(Scanner s)
{
s.readChar(); // Skip the '.'
while (s.isDigit() || s.isExponent())
{
if (s.isExponent())
return readExponent(s);
s.readChar();
}
return TokenType.Double;
}
private static TokenType? readExponent(Scanner s)
{
s.readChar(); // Skip exponent market
var read = false;
if (s.isOneOf("+-"))
{
s.readChar();
read = true;
}
while (s.isDigit())
{
read = true;
s.readChar();
}
if(read)
return TokenType.Double;
// It's not a floating point number in exponent format.
// Read it as a symbol instead.
matchSymbol(s);
return TokenType.Symbol;
}