^(??{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}
+\x{100}?(??{""})xxx xxx y $& xxx
^(.)(??{"(.)(.)"})(.)$ abcd y $1-$2 a-d
^(.)(??{"(bz+|.)(.)"})(.)$ abcd y $1-$2 a-d
^(.)((??{"(.)(cz+)"})|.) abcd y $1-$2 a-b
(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) abb y $1-$2 a-b
(a)(?:(?-1)|(?+1))(b) acb n - -
+
+(foo)(\g-2) foofoo y $1-$2 foo-foo
+(foo)(\g-2)(foo)(\g-2) foofoofoofoo y $1-$2-$3-$4 foo-foo-foo-foo
+(([abc]+) \g-1)(([abc]+) \g{-1}) abc abccba cba y $2-$4 abc-cba
+(a)(b)(c)\g1\g2\g3 abcabc y $1$2$3 abc
+
+
+/(?'n'foo) \k<n>/ ..foo foo.. y $1 foo
+/(?'n'foo) \k<n>/ ..foo foo.. y $+{n} foo
+/(?<n>foo) \k'n'/ ..foo foo.. y $1 foo
+/(?<n>foo) \k'n'/ ..foo foo.. y $+{n} foo
+/(?<as>as) (\w+) \k<as> (\w+)/ as easy as pie y $1-$2-$3 as-easy-pie