1*17f9a364Spgoyette# back references, ugh 2*17f9a364Spgoyettea\(b\)\2c bC ESUBREG 3*17f9a364Spgoyettea\(b\1\)c bC ESUBREG 4*17f9a364Spgoyettea\(b*\)c\1d b abbcbbd abbcbbd bb 5*17f9a364Spgoyettea\(b*\)c\1d b abbcbd 6*17f9a364Spgoyettea\(b*\)c\1d b abbcbbbd 7*17f9a364Spgoyette^\(.\)\1 b abc 8*17f9a364Spgoyettea\([bc]\)\1d b abcdabbd abbd b 9*17f9a364Spgoyettea\(\([bc]\)\2\)*d b abbccd abbccd 10*17f9a364Spgoyettea\(\([bc]\)\2\)*d b abbcbd 11*17f9a364Spgoyette# actually, this next one probably ought to fail, but the spec is unclear 12*17f9a364Spgoyettea\(\(b\)*\2\)*d b abbbd abbbd 13*17f9a364Spgoyette# here is a case that no NFA implementation does right 14*17f9a364Spgoyette\(ab*\)[ab]*\1 b ababaaa ababaaa a 15*17f9a364Spgoyette# check out normal matching in the presence of back refs 16*17f9a364Spgoyette\(a\)\1bcd b aabcd aabcd 17*17f9a364Spgoyette\(a\)\1bc*d b aabcd aabcd 18*17f9a364Spgoyette\(a\)\1bc*d b aabd aabd 19*17f9a364Spgoyette\(a\)\1bc*d b aabcccd aabcccd 20*17f9a364Spgoyette\(a\)\1bc*[ce]d b aabcccd aabcccd 21*17f9a364Spgoyette^\(a\)\1b\(c\)*cd$ b aabcccd aabcccd 22