question: public Seq < CharSeq > scan ( String regex ) { Pattern pat = Pattern . compile ( regex ) ; Matcher m = pat . matcher ( str ) ; MutableSeq < CharSeq > charSeq = Seqs . newMutableSeq ( ) ; while ( m . find ( ) ) { charSeq . appendInPlace ( CharSeq . of ( m . group ( ) ) ) ; } return charSeq ; }
target:  Scan through this CharSeq iteratively, generate a Seq of CharSeq with all the matching subStrings.