Excluding sequences of character using SableCC

[Cameron Ross <cross@xxxxxxxxxxxxxxxx>]

Hello,

I'm trying to derive a sablecc grammar from an existing EBNF specification.

The EBNF contains something like this:

   backslash= '\';
   digit = '0' | '1' | '2' | '3' | '4' | '5' | '6' | '7' | '8' | '9';
   numeral = digit, {digit};
   char = digit | 'A' | 'B' | 'C' | 'D' | 'E' | 'F' | 'G' | 'H' | 'I' | 
'J' | 'K' | 'L' | 'M' | 'N' | 'O' | 'P' | 'Q' | 'R' | 'S' | 'T' | 'U' | 
'V' | 'W' | 'X' | 'Y' | 'Z';
   dotschar = '...', {char};
   reserved = 'and' | 'or' | 'not';
   sequence = (char {char | backslash}), - (reservedelement | numeral | 
dotschar);

I believe that the intention of the last statement is as follows:
   - sequence should not be reserved
   - sequence should not contain only digits
   - sequence should not start with 3 dots

The sablecc example I've seen only use the except-symbol (-) for 
excluding characters and character sets from other character sets.  How 
would sequence be defined in a sablecc grammar?

Thanks in advance,
Cameron Ross.