WHITESPACE
s are only put on the HIDDEN
channel inside parser rules. Since both REGISTERLIST
and REGISTERANGE
are lexer rules, the spaces are not hidden, as you noticed. Instead of accounting for spaces inside these rules, these look to be more suitable as parser rules:
registerList : LEFTCURL REGISTER (',' REGISTER)* RIGHTCURL;
registerRange : LEFTCURL REGISTER '..' REGISTER RIGHTCURL;