I received this exception while trying to run JFlex to create a Scheme lexical analyzer for my Programming Languages course. I have never done this before, and I had never used JFlex before so this is probably a mistake I made. I am still following the instructions to try to get some help. Any help would be highly appreciated. Thanks in advance!

"Reading "Scheme.jflex"

Unexpected exception encountered. This indicates a bug in JFlex.
Please consider filing an issue at http://github.com/jflex-de/jflex/issues/new

Not normalised type = STAR
content :
type = PRIMCLASS
content :
{ [' ']['"']['('-')']['']['^']['|'] }
jflex.exceptions.CharClassException: Not normalised type = STAR
content :
type = PRIMCLASS
content :
{ [' ']['"']['('-')']['']['^']['|'] }
at jflex.core.RegExp.checkPrimClass(RegExp.java:242)
at jflex.core.RegExp.normalise(RegExp.java:323)
at jflex.core.RegExp.normalise(RegExp.java:353)
at jflex.core.RegExps.normalise(RegExps.java:293)
at jflex.core.LexParse$CUP$LexParse$actions.CUP$LexParse$do_action_part00000000(LexParse.java:1029)
at jflex.core.LexParse$CUP$LexParse$actions.CUP$LexParse$do_action(LexParse.java:2257)
at jflex.core.LexParse.do_action(LexParse.java:598)
at java_cup.runtime.lr_parser.parse(lr_parser.java:699)
at jflex.generator.LexGenerator.generate(LexGenerator.java:74)
at jflex.Main.generate(Main.java:320)
at jflex.Main.main(Main.java:336)"