# back references, ugh
a\(b\)\2c	bC	ESUBREG
a\(b\1\)c	bC	ESUBREG
a\(b*\)c\1d	b	abbcbbd	abbcbbd	bb
a\(b*\)c\1d	b	abbcbd
a\(b*\)c\1d	b	abbcbbbd
^\(.\)\1	b	abc
a\([bc]\)\1d	b	abcdabbd	abbd	b
a\(\([bc]\)\2\)*d	b	abbccd	abbccd
a\(\([bc]\)\2\)*d	b	abbcbd
# actually, this next one probably ought to fail, but the spec is unclear
a\(\(b\)*\2\)*d		b	abbbd	abbbd
# here is a case that no NFA implementation does right
\(ab*\)[ab]*\1	b	ababaaa	ababaaa	a
# check out normal matching in the presence of back refs
\(a\)\1bcd	b	aabcd	aabcd
\(a\)\1bc*d	b	aabcd	aabcd
\(a\)\1bc*d	b	aabd	aabd
\(a\)\1bc*d	b	aabcccd	aabcccd
\(a\)\1bc*[ce]d	b	aabcccd	aabcccd
^\(a\)\1b\(c\)*cd$	b	aabcccd	aabcccd