1*11be35a1SLionel Sambuc# back references, ugh 2*11be35a1SLionel Sambuca\(b\)\2c bC ESUBREG 3*11be35a1SLionel Sambuca\(b\1\)c bC ESUBREG 4*11be35a1SLionel Sambuca\(b*\)c\1d b abbcbbd abbcbbd bb 5*11be35a1SLionel Sambuca\(b*\)c\1d b abbcbd 6*11be35a1SLionel Sambuca\(b*\)c\1d b abbcbbbd 7*11be35a1SLionel Sambuc^\(.\)\1 b abc 8*11be35a1SLionel Sambuca\([bc]\)\1d b abcdabbd abbd b 9*11be35a1SLionel Sambuca\(\([bc]\)\2\)*d b abbccd abbccd 10*11be35a1SLionel Sambuca\(\([bc]\)\2\)*d b abbcbd 11*11be35a1SLionel Sambuc# actually, this next one probably ought to fail, but the spec is unclear 12*11be35a1SLionel Sambuca\(\(b\)*\2\)*d b abbbd abbbd 13*11be35a1SLionel Sambuc# here is a case that no NFA implementation does right 14*11be35a1SLionel Sambuc\(ab*\)[ab]*\1 b ababaaa ababaaa a 15*11be35a1SLionel Sambuc# check out normal matching in the presence of back refs 16*11be35a1SLionel Sambuc\(a\)\1bcd b aabcd aabcd 17*11be35a1SLionel Sambuc\(a\)\1bc*d b aabcd aabcd 18*11be35a1SLionel Sambuc\(a\)\1bc*d b aabd aabd 19*11be35a1SLionel Sambuc\(a\)\1bc*d b aabcccd aabcccd 20*11be35a1SLionel Sambuc\(a\)\1bc*[ce]d b aabcccd aabcccd 21*11be35a1SLionel Sambuc^\(a\)\1b\(c\)*cd$ b aabcccd aabcccd 22