public Token ConsumeToken(StringWalker w)
{
CodePos pos = w.Position;
string content = w.ConsumeWhile(char.IsLetterOrDigit);
return(new Token(pos, TokenType.Keyword, content));
}
public Token ConsumeToken(StringWalker w)
{
CodePos pos = w.Position;
string sign = ConsumeSign();
string wholePart = ConsumeWholePart();
string decimalPart = ConsumeDecimalPart();
string content = $"{sign}{wholePart}{decimalPart}";
return(new Token(pos, TokenType.Number, content));
string ConsumeSign() => w.Peek() == '-'
? w.Consume(1)
: "";
string ConsumeWholePart() => w.ConsumeWhile(char.IsDigit);
string ConsumeDecimalPart()
{
if (w.IsEmpty() || w.Peek() != '.')
{
return("");
}
string decimalPoint = w.Consume(1);
string digits = w.ConsumeWhile(char.IsDigit);
// If there is nothing after the decimal point, that's an error
if (digits.Length == 0)
{
throw new CompileErrorException(w.Position, "There must be digits after the decimal point");
}
// There can only be one decimal point in the number. If there's
// another, that's an error.
if (!w.IsEmpty() && w.Peek() == '.')
{
throw new CompileErrorException(w.Position, "A number may only have one decimal point");
}
return($".{digits}");
}
}
