1 # back references, ugh 2 a\(b\)\2c bC ESUBREG 3 a\(b\1\)c bC ESUBREG 4 a\(b*\)c\1d b abbcbbd abbcbbd bb 5 a\(b*\)c\1d b abbcbd 6 a\(b*\)c\1d b abbcbbbd 7 ^\(.\)\1 b abc 8 a\([bc]\)\1d b abcdabbd abbd b 9 a\(\([bc]\)\2\)*d b abbccd abbccd 10 a\(\([bc]\)\2\)*d b abbcbd 11 # actually, this next one probably ought to fail, but the spec is unclear 12 a\(\(b\)*\2\)*d b abbbd abbbd 13 # here is a case that no NFA implementation does right 14 \(ab*\)[ab]*\1 b ababaaa ababaaa a 15 # check out normal matching in the presence of back refs 16 \(a\)\1bcd b aabcd aabcd 17 \(a\)\1bc*d b aabcd aabcd 18 \(a\)\1bc*d b aabd aabd 19 \(a\)\1bc*d b aabcccd aabcccd 20 \(a\)\1bc*[ce]d b aabcccd aabcccd 21 ^\(a\)\1b\(c\)*cd$ b aabcccd aabcccd 22
Indexes created Sat Sep 20 22:09:52 GMT 2025