[antlr-interest] All except...

[Phil Oliver]

Thanks for your informative reply, Gavin. Set subtraction, even if 
only for the limited case of characters in lexer rules, would be a 
very useful addition. I did already define a new sequence along the 
lines of what you suggested but it's not nearly as clean or abstract 
as the set subtraction. Unless one has a comment or has memorized 
lots of ASCII/Unicode codes, it's not possible to tell "at a glance" 
what was omitted from the sequence when it's all additive. Kind of 
like programming in assembly rather than using a high level language.