^(\(+)?blah(?(1)(\)))$ blah y ($2) ()
^(\(+)?blah(?(1)(\)))$ blah) n - -
^(\(+)?blah(?(1)(\)))$ (blah n - -
-(?(1?)a|b) a c - Switch condition not recognized
-(?(1)a|b|c) a c - Switch (?(condition)... contains too many branches
+(?(1?)a|b) - c - Switch condition not recognized
+(?(1)a|b|c) - c - Switch (?(condition)... contains too many branches
(?(?{0})a|b) a n - -
(?(?{0})b|a) a y $& a
(?(?{1})b|a) a n - -
[a[:xyz: - c - Unmatched [
[a[:xyz:] - c - POSIX class [:xyz:] unknown
[a[:]b[:c] abc y $& abc
-([a[:xyz:]b]+) pbaq c - POSIX class [:xyz:] unknown
+([a[:xyz:]b]+) - c - POSIX class [:xyz:] unknown
[a[:]b[:c] abc y $& abc
([[:alpha:]]+) ABcd01Xy__-- ${nulnul}${ffff} y $1 ABcd
([[:alnum:]]+) ABcd01Xy__-- ${nulnul}${ffff} y $1 ABcd01Xy
^.{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
+x(?# - c - Sequence (?#... not terminated
+: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
(?P<n>foo|bar|baz)(?P<m>[ew]+) snofooewa yM $+{m} ew miniperl cannot load Tie::Hash::NamedCapture
(?P<n>foo)|(?P<n>bar)|(?P<n>baz) snofooewa yM $+{n} foo miniperl cannot load Tie::Hash::NamedCapture
(?P<n>foo)(??{ $+{n} }) snofooefoofoowaa yM $+{n} foo miniperl cannot load Tie::Hash::NamedCapture
-(?P<=n>foo|bar|baz) snofooewa c - Group name must start with a non-digit word character
-(?P<!n>foo|bar|baz) snofooewa c - Group name must start with a non-digit word character
-(?PX<n>foo|bar|baz) snofooewa c - Sequence (?PX<...) not recognized
+(?P<=n>foo|bar|baz) - c - Group name must start with a non-digit word character
+(?P<!n>foo|bar|baz) - c - Group name must start with a non-digit word character
+(?PX<n>foo|bar|baz) - c - Sequence (?PX<...) not recognized
/(?'n'foo|bar|baz)/ snofooewa y $1 foo
/(?'n'foo|bar|baz)/ snofooewa yM $+{n} foo miniperl cannot load Tie::Hash::NamedCapture
/(?'n'foo|bar|baz)(?'m'[ew]+)/ snofooewa yM $+{n} foo miniperl cannot load Tie::Hash::NamedCapture
/(?<_>foo) \k<_>/ ..foo foo.. yM $+{_} foo miniperl cannot load Tie::Hash::NamedCapture
/(?'_0_'foo) \k'_0_'/ ..foo foo.. yM $+{_0_} foo miniperl cannot load Tie::Hash::NamedCapture
/(?<_0_>foo) \k<_0_>/ ..foo foo.. yM $+{_0_} foo miniperl cannot load Tie::Hash::NamedCapture
-/(?'0'foo) bar/ ..foo bar.. c - Group name must start with a non-digit word character
-/(?<0>foo) bar/ ..foo bar.. c - Group name must start with a non-digit word character
-/(?'12'foo) bar/ ..foo bar.. c - Group name must start with a non-digit word character
-/(?<12>foo) bar/ ..foo bar.. c - Group name must start with a non-digit word character
-/(?'1a'foo) bar/ ..foo bar.. c - Group name must start with a non-digit word character
-/(?<1a>foo) bar/ ..foo bar.. c - Group name must start with a non-digit word character
-/(?''foo) bar/ ..foo bar.. c - Group name must start with a non-digit word character
-/(?<>foo) bar/ ..foo bar.. c - Group name must start with a non-digit word character
-/foo \k'n'/ foo foo c - Reference to nonexistent named group
-/foo \k<n>/ foo foo c - Reference to nonexistent named group
-/foo \k'a1'/ foo foo c - Reference to nonexistent named group
-/foo \k<a1>/ foo foo c - Reference to nonexistent named group
-/foo \k'_'/ foo foo c - Reference to nonexistent named group
-/foo \k<_>/ foo foo c - Reference to nonexistent named group
-/foo \k'_0_'/ foo foo c - Reference to nonexistent named group
-/foo \k<_0_>/ foo foo c - Reference to nonexistent named group
-/foo \k'0'/ foo foo c - Group name must start with a non-digit word character
-/foo \k<0>/ foo foo c - Group name must start with a non-digit word character
-/foo \k'12'/ foo foo c - Group name must start with a non-digit word character
-/foo \k<12>/ foo foo c - Group name must start with a non-digit word character
-/foo \k'1a'/ foo foo c - Group name must start with a non-digit word character
-/foo \k<1a>/ foo foo c - Group name must start with a non-digit word character
-/foo \k''/ foo foo c - Group name must start with a non-digit word character
-/foo \k<>/ foo foo c - Group name must start with a non-digit word character
+/(?'0'foo) bar/ - c - Group name must start with a non-digit word character
+/(?<0>foo) bar/ - c - Group name must start with a non-digit word character
+/(?'12'foo) bar/ - c - Group name must start with a non-digit word character
+/(?<12>foo) bar/ - c - Group name must start with a non-digit word character
+/(?'1a'foo) bar/ - c - Group name must start with a non-digit word character
+/(?<1a>foo) bar/ - c - Group name must start with a non-digit word character
+/(?''foo) bar/ - c - Group name must start with a non-digit word character
+/(?<>foo) bar/ - c - Group name must start with a non-digit word character
+/foo \k'n'/ - c - Reference to nonexistent named group
+/foo \k<n>/ - c - Reference to nonexistent named group
+/foo \k'a1'/ - c - Reference to nonexistent named group
+/foo \k<a1>/ - c - Reference to nonexistent named group
+/foo \k'_'/ - c - Reference to nonexistent named group
+/foo \k<_>/ - c - Reference to nonexistent named group
+/foo \k'_0_'/ - c - Reference to nonexistent named group
+/foo \k<_0_>/ - c - Reference to nonexistent named group
+/foo \k'0'/ - c - Group name must start with a non-digit word character
+/foo \k<0>/ - c - Group name must start with a non-digit word character
+/foo \k'12'/ - c - Group name must start with a non-digit word character
+/foo \k<12>/ - c - Group name must start with a non-digit word character
+/foo \k'1a'/ - c - Group name must start with a non-digit word character
+/foo \k<1a>/ - c - Group name must start with a non-digit word character
+/foo \k''/ - c - Group name must start with a non-digit word character
+/foo \k<>/ - c - Group name must start with a non-digit word character
/(?<as>as) (\w+) \k<as> (\w+)/ as easy as pie y $1-$2-$3 as-easy-pie
# \g{...} with a name as the argument