+^(a(b)?)+$ aba y -$1-$2- -a--
+^(aa(bb)?)+$ aabbaa y -$1-$2- -aa--
+'^.{9}abc.*\n'm 123\nabcabcabcabc\n y - -
+^(a)?a$ a y -$1- --
+^(a)?(?(1)a|b)+$ a n - -
+^(a\1?)(a\1?)(a\2?)(a\3?)$ aaaaaa y $1,$2,$3,$4 a,aa,a,aa
+^(a\1?){4}$ aaaaaa y $1 aa
+^(0+)?(?:x(1))? x1 y - -
+^([0-9a-fA-F]+)(?:x([0-9a-fA-F]+)?)(?:x([0-9a-fA-F]+))? 012cxx0190 y - -
+^(b+?|a){1,2}c bbbac y $1 a
+^(b+?|a){1,2}c bbbbac y $1 a
+\((\w\. \w+)\) cd. (A. Tw) y -$1- -A. Tw-
+((?:aaaa|bbbb)cccc)? aaaacccc y - -
+((?:aaaa|bbbb)cccc)? bbbbcccc y - -
+(a)?(a)+ a y $1:$2 :a -
+(ab)?(ab)+ ab y $1:$2 :ab -
+(abc)?(abc)+ abc y $1:$2 :abc -
+'b\s^'m a\nb\n n - -
+\ba a y - -
+^(a(??{"(?!)"})|(a)(?{1}))b ab y $2 a # [ID 20010811.006]
+ab(?i)cd AbCd n - - # [ID 20010809.023]
+ab(?i)cd abCd y - -
+(A|B)*(?(1)(CD)|(CD)) CD y $2-$3 -CD
+(A|B)*(?(1)(CD)|(CD)) ABCD y $2-$3 CD-
+(A|B)*?(?(1)(CD)|(CD)) CD y $2-$3 -CD # [ID 20010803.016]
+(A|B)*?(?(1)(CD)|(CD)) ABCD y $2-$3 CD-
+'^(o)(?!.*\1)'i Oo n - -
+(.*)\d+\1 abc12bc y $1 bc
+(?m:(foo\s*$)) foo\n bar y $1 foo
+(.*)c abcd y $1 ab
+(.*)(?=c) abcd y $1 ab
+(.*)(?=c)c abcd yB $1 ab
+(.*)(?=b|c) abcd y $1 ab
+(.*)(?=b|c)c abcd y $1 ab
+(.*)(?=c|b) abcd y $1 ab
+(.*)(?=c|b)c abcd y $1 ab
+(.*)(?=[bc]) abcd y $1 ab
+(.*)(?=[bc])c abcd yB $1 ab
+(.*)(?<=b) abcd y $1 ab
+(.*)(?<=b)c abcd y $1 ab
+(.*)(?<=b|c) abcd y $1 abc
+(.*)(?<=b|c)c abcd y $1 ab
+(.*)(?<=c|b) abcd y $1 abc
+(.*)(?<=c|b)c abcd y $1 ab
+(.*)(?<=[bc]) abcd y $1 abc
+(.*)(?<=[bc])c abcd y $1 ab
+(.*?)c abcd y $1 ab
+(.*?)(?=c) abcd y $1 ab
+(.*?)(?=c)c abcd yB $1 ab
+(.*?)(?=b|c) abcd y $1 a
+(.*?)(?=b|c)c abcd y $1 ab
+(.*?)(?=c|b) abcd y $1 a
+(.*?)(?=c|b)c abcd y $1 ab
+(.*?)(?=[bc]) abcd y $1 a
+(.*?)(?=[bc])c abcd yB $1 ab
+(.*?)(?<=b) abcd y $1 ab
+(.*?)(?<=b)c abcd y $1 ab
+(.*?)(?<=b|c) abcd y $1 ab
+(.*?)(?<=b|c)c abcd y $1 ab
+(.*?)(?<=c|b) abcd y $1 ab
+(.*?)(?<=c|b)c abcd y $1 ab
+(.*?)(?<=[bc]) abcd y $1 ab
+(.*?)(?<=[bc])c abcd y $1 ab
+2(]*)?$\1 2 y $& 2
+(??{}) x y - -
+a(b)?? abc y <$1> <> # undef [perl #16773]
+(\d{1,3}\.){3,} 128.134.142.8 y <$1> <142.> # [perl #18019]
+^.{3,4}(.+)\1\z foobarbar y $1 bar # 16 tests for [perl #23171]
+^(?:f|o|b){3,4}(.+)\1\z foobarbar y $1 bar
+^.{3,4}((?:b|a|r)+)\1\z foobarbar y $1 bar
+^(?:f|o|b){3,4}((?:b|a|r)+)\1\z foobarbar y $1 bar
+^.{3,4}(.+?)\1\z foobarbar y $1 bar
+^(?:f|o|b){3,4}(.+?)\1\z foobarbar y $1 bar
+^.{3,4}((?:b|a|r)+?)\1\z foobarbar y $1 bar
+^(?:f|o|b){3,4}((?:b|a|r)+?)\1\z foobarbar y $1 bar
+^.{2,3}?(.+)\1\z foobarbar y $1 bar
+^(?:f|o|b){2,3}?(.+)\1\z foobarbar y $1 bar
+^.{2,3}?((?:b|a|r)+)\1\z foobarbar y $1 bar
+^(?:f|o|b){2,3}?((?:b|a|r)+)\1\z foobarbar y $1 bar
+^.{2,3}?(.+?)\1\z foobarbar y $1 bar
+^(?:f|o|b){2,3}?(.+?)\1\z foobarbar y $1 bar
+^.{2,3}?((?:b|a|r)+?)\1\z foobarbar y $1 bar
+^(?:f|o|b){2,3}?((?:b|a|r)+?)\1\z foobarbar y $1 bar
+.*a(?!(b|cd)*e).*f ......abef n - - # [perl #23030]
+x(?# x c - Sequence (?#... not terminated
+:x(?#: x c - Sequence (?#... not terminated
+(WORDS|WORD)S WORDS y $1 WORD
+(X.|WORDS|X.|WORD)S WORDS y $1 WORD
+(WORDS|WORLD|WORD)S WORDS y $1 WORD
+(X.|WORDS|WORD|Y.)S WORDS y $1 WORD
+(foo|fool|x.|money|parted)$ fool y $1 fool
+(x.|foo|fool|x.|money|parted|y.)$ fool y $1 fool
+(foo|fool|money|parted)$ fool y $1 fool
+(foo|fool|x.|money|parted)$ fools n - -
+(x.|foo|fool|x.|money|parted|y.)$ fools n - -
+(foo|fool|money|parted)$ fools n - -
+(a|aa|aaa||aaaa|aaaaa|aaaaaa)(b|c) aaaaaaaaaaaaaaab y $1$2 aaaaaab
+(a|aa|aaa||aaaa|aaaaa|aaaaaa)(??{$1&&""})(b|c) aaaaaaaaaaaaaaab y $1$2 aaaaaab
+(a|aa|aaa|aaaa|aaaaa|aaaaaa)(??{$1&&"foo"})(b|c) aaaaaaaaaaaaaaab n - -
+^(a*?)(?!(aa|aaaa)*$) aaaaaaaaaaaaaaaaaaaa y $1 a # [perl #34195]
+^(a*?)(?!(aa|aaaa)*$)(?=a\z) aaaaaaaa y $1 aaaaaaa
+^(.)\s+.$(?(1)) A B y $1 A # [perl #37688]
+(?:r?)*?r|(.{2,4}) abcde y $1 abcd
+(?!)+?|(.{2,4}) abcde y $1 abcd
+^(a*?)(?!(a{6}|a{5})*$) aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa y $+[1] 12 # super-linear cache bug may return 18
+^((?>(?:aa)?b)?) aab y $1 aab
+^((?:aa)*)(?:X+((?:\d+|-)(?:X+(.+))?))?$ aaaaX5 y $1 aaaa
+X(A|B||C|D)Y XXXYYY y $& XY # Trie w/ NOTHING
+(?i:X([A]|[B]|y[Y]y|[D]|)Y) XXXYYYB y $& XY # Trie w/ NOTHING
+^([a]{1})*$ aa y $1 a
+a(?!b(?!c))(..) abababc y $1 bc # test nested negatives
+a(?!b(?=a))(..) abababc y $1 bc # test nested lookaheads
+a(?!b(?!c(?!d(?!e))))...(.) abxabcdxabcde y $1 e
+X(?!b+(?!(c+)*(?!(c+)*d))).*X aXbbbbbbbcccccccccccccaaaX y - -
+^(XXXXXXXXXX|YYYYYYYYYY|Z.Q*X|Z[TE]Q*P): ZEQQQQQQQQQQQQQQQQQQP: y $1 ZEQQQQQQQQQQQQQQQQQQP
+^(XXXXXXXXXX|YYYYYYYYYY|Z.Q*X|Z[TE]Q*P): ZEQQQX: y $1 ZEQQQX
+^([TUV]+|XXXXXXXXXX|YYYYYYYYYY|Z.Q*X|Z[TE]Q*P): ZEQQQQQQQQQQQQQQQQQQP: y $1 ZEQQQQQQQQQQQQQQQQQQP
+^([TUV]+|XXXXXXXXXX|YYYYYYYYYY|Z.Q*X|Z[TE]Q*P): ZEQQQX: y $1 ZEQQQX
+^([TUV]+|XXXXXXXXXX|YYYYYYYYYY|Z.Q*X|Z[TE]Q*P|[MKJ]): ZEQQQQQQQQQQQQQQQQQQP: y $1 ZEQQQQQQQQQQQQQQQQQQP
+^([TUV]+|XXXXXXXXXX|YYYYYYYYYY|Z.Q*X|Z[TE]Q*P|[MKJ]): ZEQQQX: y $1 ZEQQQX
+^(XXX|YYY|Z.Q*X|Z[TE]Q*P): ZEQQQQQQQQQQQQQQQQQQP: y $1 ZEQQQQQQQQQQQQQQQQQQP
+^(XXX|YYY|Z.Q*X|Z[TE]Q*P): ZEQQQX: y $1 ZEQQQX
+^([TUV]+|XXX|YYY|Z.Q*X|Z[TE]Q*P): ZEQQQQQQQQQQQQQQQQQQP: y $1 ZEQQQQQQQQQQQQQQQQQQP
+^([TUV]+|XXX|YYY|Z.Q*X|Z[TE]Q*P): ZEQQQX: y $1 ZEQQQX
+^([TUV]+|XXX|YYY|Z.Q*X|Z[TE]Q*P|[MKJ]): ZEQQQQQQQQQQQQQQQQQQP: y $1 ZEQQQQQQQQQQQQQQQQQQP
+^([TUV]+|XXX|YYY|Z.Q*X|Z[TE]Q*P|[MKJ]): ZEQQQX: y $1 ZEQQQX
+X(?:ABCF[cC]x*|ABCD|ABCF):(?:DIT|DID|DIM) XABCFCxxxxxxxxxx:DIM y $& XABCFCxxxxxxxxxx:DIM
+(((ABCD|ABCE|ABCF)))(A|B|C[xy]*): ABCFCxxxxxxxxxx:DIM y $& ABCFCxxxxxxxxxx:
+(?=foo) foo y pos 0
+(?=foo) XfooY y pos 1
+.*(?=foo) XfooY y pos 1
+(?<=foo) foo y pos 3
+(?<=foo) XfooY y pos 4
+.*(?<=foo) foo y pos 3
+.*(?<=foo) XfooY y pos 4
+(?<=foo)Y XfooY y pos 5
+o(?<=foo)Y ..XfooY.. y pos 7
+X(?=foo)f ..XfooY.. y pos 4
+X(?=foo) ..XfooY.. y pos 3
+X(?<=foo.)[YZ] ..XfooXY.. y pos 8
+(?=XY*foo) Xfoo y pos 0
+^(?=XY*foo) Xfoo y pos 0
+^(??{"a+"})a aa y $& aa
+^(?:(??{"a+"})|b)a aa y $& aa
+^(??{chr 0x100}).$ \x{100}\x{100} y $& \x{100}\x{100}
+^(??{q(\x{100})}). \x{100}\x{100} y $& \x{100}\x{100}
+^(??{q(.+)})\x{100} \x{100}\x{100} y $& \x{100}\x{100}
+^(??{q(.)})\x{100} \x{100}\x{100} y $& \x{100}\x{100}
+^(??{chr 0x100})\xbb \x{100}\x{bb} y $& \x{100}\x{bb}
+^(.)(??{"(.)(.)"})(.)$ abcd y $1-$2 a-d
+^(.)(??{"(bz+|.)(.)"})(.)$ abcd y $1-$2 a-d
+^(.)((??{"(.)(cz+)"})|.) abcd y $1-$2 a-b
+^a(?>(??{q(b)}))(??{q(c)})d abcd y - -
+^x(??{""})+$ x y $& x
+^(<(?:[^<>]+|(?3)|(?1))*>)()(!>!>!>)$ <<!>!>!>><>>!>!>!> y $1 <<!>!>!>><>>
+^(<(?:[^<>]+|(?1))*>)$ <<><<<><>>>> y $1 <<><<<><>>>>
+((?2)*)([fF]o+) fooFoFoo y $1-$2 fooFo-Foo
+(<(?:[^<>]+|(?R))*>) <<><<<><>>>> y $1 <<><<<><>>>>
+(?<n>foo|bar|baz) snofooewa y $1 foo
+(?<n>foo|bar|baz) snofooewa y $+{n} foo
+(?<n>foo|bar|baz)(?<m>[ew]+) snofooewa y $+{n} foo
+(?<n>foo|bar|baz)(?<m>[ew]+) snofooewa y $+{m} ew
+(?<n>foo)|(?<n>bar)|(?<n>baz) snofooewa y $+{n} foo
+(?<n>foo)(??{ $+{n} }) snofooefoofoowaa y $+{n} foo
+/(?'n'foo|bar|baz)/ snofooewa y $1 foo
+/(?'n'foo|bar|baz)/ snofooewa y $+{n} foo
+/(?'n'foo|bar|baz)(?'m'[ew]+)/ snofooewa y $+{n} foo
+/(?'n'foo|bar|baz)(?'m'[ew]+)/ snofooewa y $+{m} ew
+/(?'n'foo)|(?'n'bar)|(?<n>baz)/ snobazewa y $+{n} baz
+/(?'n'foo)(??{ $+{n} })/ snofooefoofoowaa y $+{n} foo
+/(?'n'foo)\k<n>/ ..foofoo.. y $1 foo
+/(?'n'foo)\k<n>/ ..foofoo.. y $+{n} foo
+/(?<n>foo)\k'n'/ ..foofoo.. y $1 foo
+/(?<n>foo)\k'n'/ ..foofoo.. y $+{n} foo
+/(?:(?<n>foo)|(?<n>bar))\k<n>/ ..barbar.. y $+{n} bar
+/^(?'main'<(?:[^<>]+|(?&crap)|(?&main))*>)(?'empty')(?'crap'!>!>!>)$/ <<!>!>!>><>>!>!>!> y $+{main} <<!>!>!>><>>
+/^(?'main'<(?:[^<>]+|(?&main))*>)$/ <<><<<><>>>> y $1 <<><<<><>>>>
+/(?'first'(?&second)*)(?'second'[fF]o+)/ fooFoFoo y $+{first}-$+{second} fooFo-Foo
+(?<A>foo)?(?(<A>)bar|nada) foobar y $+{A} foo
+(?<A>foo)?(?(<A>)bar|nada) foo-barnada y $& nada
+(?<A>foo)?(?(1)bar|nada) foo-barnada y $& nada
+(?<A>foo(?(R)bar))?(?1) foofoobar y $1 foo
+(?<A>foo(?(R)bar))?(?1) foofoobar y $& foofoobar
+(x)(?<A>foo(?(R&A)bar))?(?&A) xfoofoobar y $2 foo
+(x)(?<A>foo(?(R&A)bar))?(?&A) xfoofoobar y $& xfoofoobar
+(x)(?<A>foo(?(R2)bar))?(?&A) xfoofoobar y $2 foo
+(x)(?<A>foo(?(R2)bar))?(?&A) xfoofoobar y $& xfoofoobar
+(?1)(?(DEFINE)(blah)) blah y $& blah
+/^(?<PAL>(?<CHAR>.)((?&PAL)|.?)\k<CHAR>)$/ madamimadam y $& madamimadam
+/^(?<PAL>(?<CHAR>.)((?&PAL)|.?)\k<CHAR>)$/ madamiamadam n - -
+/(a)?((?1))(fox)/ aafox y $1-$2-$3 a-a-fox
+/(a)*((?1))(fox)/ aafox y $1-$2-$3 a-a-fox
+/(a)+((?1))(fox)/ aafox y $1-$2-$3 a-a-fox
+/(a){1,100}((?1))(fox)/ aafox y $1-$2-$3 a-a-fox
+/(a){0,100}((?1))(fox)/ aafox y $1-$2-$3 a-a-fox
+/(ab)?((?1))(fox)/ ababfox y $1-$2-$3 ab-ab-fox
+/(ab)*((?1))(fox)/ ababfox y $1-$2-$3 ab-ab-fox
+/(ab)+((?1))(fox)/ ababfox y $1-$2-$3 ab-ab-fox
+/(ab){1,100}((?1))(fox)/ ababfox y $1-$2-$3 ab-ab-fox
+/(ab){0,100}((?1))(fox)/ ababfox y $1-$2-$3 ab-ab-fox
+# possessive captures
+a++a aaaaa n - -
+a*+a aaaaa n - -
+a{1,5}+a aaaaa n - -
+a?+a ab n - -
+a++b aaaaab y $& aaaaab
+a*+b aaaaab y $& aaaaab
+a{1,5}+b aaaaab y $& aaaaab
+a?+b ab y $& ab
+fooa++a fooaaaaa n - -
+fooa*+a fooaaaaa n - -
+fooa{1,5}+a fooaaaaa n - -
+fooa?+a fooab n - -
+fooa++b fooaaaaab y $& fooaaaaab
+fooa*+b fooaaaaab y $& fooaaaaab
+fooa{1,5}+b fooaaaaab y $& fooaaaaab
+fooa?+b fooab y $& fooab
+(?:aA)++(?:aA) aAaAaAaAaA n - aAaAaAaAaA
+(aA)++(aA) aAaAaAaAaA n - aAaAaAaAaA
+(aA|bB)++(aA|bB) aAaAbBaAbB n - aAaAbBaAbB
+(?:aA|bB)++(?:aA|bB) aAbBbBbBaA n - aAbBbBbBaA
+(?:aA)*+(?:aA) aAaAaAaAaA n - aAaAaAaAaA
+(aA)*+(aA) aAaAaAaAaA n - aAaAaAaAaA
+(aA|bB)*+(aA|bB) aAaAbBaAaA n - aAaAbBaAaA
+(?:aA|bB)*+(?:aA|bB) aAaAaAbBaA n - aAaAaAbBaA
+(?:aA){1,5}+(?:aA) aAaAaAaAaA n - aAaAaAaAaA
+(aA){1,5}+(aA) aAaAaAaAaA n - aAaAaAaAaA
+(aA|bB){1,5}+(aA|bB) aAaAbBaAaA n - aAaAbBaAaA
+(?:aA|bB){1,5}+(?:aA|bB) bBbBbBbBbB n - bBbBbBbBbB
+(?:aA)?+(?:aA) aAb n - aAb
+(aA)?+(aA) aAb n - aAb
+(aA|bB)?+(aA|bB) bBb n - bBb
+(?:aA|bB)?+(?:aA|bB) aAb n - aAb
+(?:aA)++b aAaAaAaAaAb y $& aAaAaAaAaAb
+(aA)++b aAaAaAaAaAb y $& aAaAaAaAaAb
+(aA|bB)++b aAbBaAaAbBb y $& aAbBaAaAbBb
+(?:aA|bB)++b aAbBbBaAaAb y $& aAbBbBaAaAb
+(?:aA)*+b aAaAaAaAaAb y $& aAaAaAaAaAb
+(aA)*+b aAaAaAaAaAb y $& aAaAaAaAaAb
+(aA|bB)*+b bBbBbBbBbBb y $& bBbBbBbBbBb
+(?:aA|bB)*+b bBaAbBbBaAb y $& bBaAbBbBaAb
+(?:aA){1,5}+b aAaAaAaAaAb y $& aAaAaAaAaAb
+(aA){1,5}+b aAaAaAaAaAb y $& aAaAaAaAaAb
+(aA|bB){1,5}+b bBaAbBaAbBb y $& bBaAbBaAbBb
+(?:aA|bB){1,5}+b aAbBaAbBbBb y $& aAbBaAbBbBb
+(?:aA)?+b aAb y $& aAb
+(aA)?+b aAb y $& aAb
+(aA|bB)?+b bBb y $& bBb
+(?:aA|bB)?+b bBb y $& bBb
+foo(?:aA)++(?:aA) fooaAaAaAaAaA n - fooaAaAaAaAaA
+foo(aA)++(aA) fooaAaAaAaAaA n - fooaAaAaAaAaA
+foo(aA|bB)++(aA|bB) foobBbBbBaAaA n - foobBbBbBaAaA
+foo(?:aA|bB)++(?:aA|bB) fooaAaAaAaAaA n - fooaAaAaAaAaA
+foo(?:aA)*+(?:aA) fooaAaAaAaAaA n - fooaAaAaAaAaA
+foo(aA)*+(aA) fooaAaAaAaAaA n - fooaAaAaAaAaA
+foo(aA|bB)*+(aA|bB) foobBaAbBaAaA n - foobBaAbBaAaA
+foo(?:aA|bB)*+(?:aA|bB) fooaAaAbBbBaA n - fooaAaAbBbBaA
+foo(?:aA){1,5}+(?:aA) fooaAaAaAaAaA n - fooaAaAaAaAaA
+foo(aA){1,5}+(aA) fooaAaAaAaAaA n - fooaAaAaAaAaA
+foo(aA|bB){1,5}+(aA|bB) fooaAbBbBaAaA n - fooaAbBbBaAaA
+foo(?:aA|bB){1,5}+(?:aA|bB) fooaAbBbBaAbB n - fooaAbBbBaAbB
+foo(?:aA)?+(?:aA) fooaAb n - fooaAb
+foo(aA)?+(aA) fooaAb n - fooaAb
+foo(aA|bB)?+(aA|bB) foobBb n - foobBb
+foo(?:aA|bB)?+(?:aA|bB) fooaAb n - fooaAb
+foo(?:aA)++b fooaAaAaAaAaAb y $& fooaAaAaAaAaAb
+foo(aA)++b fooaAaAaAaAaAb y $& fooaAaAaAaAaAb
+foo(aA|bB)++b foobBaAbBaAbBb y $& foobBaAbBaAbBb
+foo(?:aA|bB)++b fooaAaAbBaAaAb y $& fooaAaAbBaAaAb
+foo(?:aA)*+b fooaAaAaAaAaAb y $& fooaAaAaAaAaAb
+foo(aA)*+b fooaAaAaAaAaAb y $& fooaAaAaAaAaAb
+foo(aA|bB)*+b foobBbBaAaAaAb y $& foobBbBaAaAaAb
+foo(?:aA|bB)*+b foobBaAaAbBaAb y $& foobBaAaAbBaAb
+foo(?:aA){1,5}+b fooaAaAaAaAaAb y $& fooaAaAaAaAaAb
+foo(aA){1,5}+b fooaAaAaAaAaAb y $& fooaAaAaAaAaAb
+foo(aA|bB){1,5}+b foobBaAaAaAaAb y $& foobBaAaAaAaAb
+foo(?:aA|bB){1,5}+b fooaAbBaAbBbBb y $& fooaAbBaAbBbBb
+foo(?:aA)?+b fooaAb y $& fooaAb
+foo(aA)?+b fooaAb y $& fooaAb
+foo(aA|bB)?+b foobBb y $& foobBb
+foo(?:aA|bB)?+b foobBb y $& foobBb
+
+([^()]++|\([^()]*\))+ ((abc(ade)ufh()()x y $& abc(ade)ufh()()x
+round\(([^()]++)\) _I(round(xs * sz),1) y $1 xs * sz
+
+(foo[1x]|bar[2x]|baz[3x])+y foo1bar2baz3y y $1 baz3
+(foo[1x]|bar[2x]|baz[3x])+y foo1bar2baz3y y $& foo1bar2baz3y
+(foo[1x]|bar[2x]|baz[3x])*y foo1bar2baz3y y $1 baz3
+(foo[1x]|bar[2x]|baz[3x])*y foo1bar2baz3y y $& foo1bar2baz3y
+
+([yX].|WORDS|[yX].|WORD)S WORDS y $1 WORD
+(WORDS|WORLD|WORD)S WORDS y $1 WORD
+([yX].|WORDS|WORD|[xY].)S WORDS y $1 WORD
+(foo|fool|[zx].|money|parted)$ fool y $1 fool
+([zx].|foo|fool|[zq].|money|parted|[yx].)$ fool y $1 fool
+(foo|fool|[zx].|money|parted)$ fools n - -
+([zx].|foo|fool|[qx].|money|parted|[py].)$ fools n - -
+
+([yX].|WORDS|[yX].|WORD)+S WORDS y $1 WORD
+(WORDS|WORLD|WORD)+S WORDS y $1 WORD
+([yX].|WORDS|WORD|[xY].)+S WORDS y $1 WORD
+(foo|fool|[zx].|money|parted)+$ fool y $1 fool
+([zx].|foo|fool|[zq].|money|parted|[yx].)+$ fool y $1 fool
+(foo|fool|[zx].|money|parted)+$ fools n - -
+([zx].|foo|fool|[qx].|money|parted|[py].)+$ fools n - -
+
+(x|y|z[QW])+(longish|loquatious|excessive|overblown[QW])+ xyzQzWlongishoverblownW y $1-$2 zW-overblownW
+(x|y|z[QW])*(longish|loquatious|excessive|overblown[QW])* xyzQzWlongishoverblownW y $1-$2 zW-overblownW
+(x|y|z[QW]){1,5}(longish|loquatious|excessive|overblown[QW]){1,5} xyzQzWlongishoverblownW y $1-$2 zW-overblownW
+
+(x|y|z[QW])++(longish|loquatious|excessive|overblown[QW])++ xyzQzWlongishoverblownW y $1-$2 zW-overblownW
+(x|y|z[QW])*+(longish|loquatious|excessive|overblown[QW])*+ xyzQzWlongishoverblownW y $1-$2 zW-overblownW
+(x|y|z[QW]){1,5}+(longish|loquatious|excessive|overblown[QW]){1,5}+ xyzQzWlongishoverblownW y $1-$2 zW-overblownW
+
+
+a*(?!) aaaab n - -
+a*(*FAIL) aaaab n - -
+a*(*F) aaaab n - -
+
+(A(A|B(*ACCEPT)|C)D)(E) AB y $1 AB
+(A(A|B(*ACCEPT)|C)D)(E) ACDE y $1$2$3 ACDCE
+
+(a)(?:(?-1)|(?+1))(b) aab y $&-$1-$2 aab-a-b
+(a)(?:(?-1)|(?+1))(b) abb y $&-$1-$2 abb-a-b
+(a)(?:(?-1)|(?+1))(b) acb n - -