6 ['<code>use warnings</code>', 'pragma to enable warnings in lexical scope'],
7 ['<code>use utf8</code>', 'experimental unicode semantics <small>(completed in v5.8)</small>', v5.8],
8 ['<code>use charnames</code>', 'string escape <code>\N{}</code> to insert named character'],
9 ['<code>our</code>', 'declare global variables'],
10 ['<code>v1.2.3</code>', q`represent strings as vector of ordinals, useful in version numbers (<code>printf '%vd'</code> to display)`],
11 ['<code>0b0</code>', q`binary numbers in literals, <code>printf '%b'</code>, and <code>oct</code>`],
12 ['<code>sub :lvalue</code>', 'subroutine attribute to return a modifiable value', v5.20],
13 # ['<code>sub :locked :method</code>', 'syntax to declare subroutine attributes'], # can be inferred from :lvalue support
14 ['<code>open my $fh, $mode, $expr</code>', 'file handles in scoped scalars, third argument for unambiguous file name'],
15 [q`<code>pack 'q'</code>`, '64-bit integer support (also large files >2GiB)', v5.8.1],
16 ['<code>sort $coderef ()</code>', 'comparison function can be a subroutine reference; prototype <code>($$)</code> to pass elements as normal <code>@_</code>'],
17 ['<code>CHECK {}</code>', 'special block called at end of compilation'],
18 ['<code>/[[:…:]]/</code>', 'POSIX character class syntax such as <code>/[[:alpha:]]/</code>'],
19 # quite a lot more, but leave it at this
21 release => '2000-03-23',
24 rhel => '2', # v5.6.0; also in red hat 7.0
25 solaris => '9', # v5.6.1; 2002-05 eol 2014-10
32 [q`<code>no utf8</code>`, 'full unicode support, <code>utf8</code> pragma only for script encoding'],
33 [q`<code>binmode $fh, ':perlio'</code>`, 'file handle behaviour altered by PerlIO layers'],
34 [q`<code>open $fh, '-|', @cmd</code>`, 'open list to fork a command without spawning a shell'],
35 [q`<code>open $fh, '>', \$var</code>`, 'perl scalars as virtual files'],
36 [q`<code>printf '%1$s', @args</code>`, 'syntax to use parameters out of order'],
37 [q`<code>1_2_3 == 123</code>`, 'underscores between digits allowed in numeric constants'],
38 # [q`<code>use if</code>`, 'conditional module inclusion'], # also installable in earlier versions
40 release => '2002-07-18',
43 rhel => '3', # v5.8.0; v5.8.8 in RHEL6 (2007-2014)
44 solaris => '10', # v5.8.4; 2005-01 eol 2021-01
45 centos => '3-5', # v5.8.0 in v3 (2004-03); v5.8.8 in v5 (eol 2017-03)
52 ['<code>//</code>', 'defined-or operator'],
53 ['<code>~~</code>', 'smart-match operator to compare different data types <small>(updated in v5.10.1)</small>', 'experimental::smartmatch'],
54 ['<code>given</code>', 'switch statement to smart-match with <code>when</code>/<code>default</code>', 'experimental::smartmatch'],
55 ['<code>/(?<name>)/</code>', 'named capture buffers into <code>%+</code>'],
56 ['<code>s/keep\K//</code>', 'floating positive lookbehind, efficient alternative for <code>s/(keep)/$1/</code>'],
57 ['<code>/\v/, /\h/</code>', 'vertical and horizontal whitespace escapes'],
58 ['<code>my $_</code>', 'lexically scoped version of the default variable', 'experimental::lexical_topic'],
60 release => '2007-12-18',
63 rhel => '6', # v5.10.1
64 centos => '6', # v5.10.1 (2011-07 eol 2020-11)
71 ['<code>package version</code>', '<code>package</code> NAME VERSION shorthand for <code>our $VERSION</code>'],
72 ['<code>...</code>', 'yada-yada operator: code placeholder'],
73 ['<code>use 5.012</code>', 'Implicit <code>strict</code> if use VERSION >= v5.12'],
74 ['<code>… when</code>', '<code>when</code> is now allowed to be used as a statement modifier'],
75 [q(<code>use overload 'qr'</code>), 'customisable conversion to regular expressions'],
76 ['<code>/\N/</code>', 'inverse \n to match any character except newline regardless of <code>/s</code>', v5.18],
78 release => '2010-04-12',
81 solaris => '11', # also v5.8.4; 2010-11 eol 2024-11
87 ['<code>s///r</code>', 'non-destructive substitution'],
88 ['<code>/(?^)/</code>', 'construct to reset to default modifiers'],
89 ['<code>/(?{ m() })/</code>', 'regular expressions can be nested in <code>/(?{})/</code> and <code>/(??{})/</code>', v5.20],
90 ["<code>use re '/flags'</code>", 'customise default modifiers'],
91 ['<code>each $ref</code> e.a.', 'array and hash container functions accept references', ''],
92 ['<code>FH->method</code>', 'filehandle method calls load IO::File on demand (eg. <code>STDOUT->flush</code>)'],
94 release => '2011-05-14',
103 ['<code>__SUB__</code>', 'current subroutine reference'],
104 ['<code>fc, "\F"</code>', 'unicode foldcase to compare case-insensitively'],
105 ['<code>"\N{}"</code>', 'automatic <code>use charnames qw( :full :short )</code>'],
107 release => '2012-05-20',
109 rhel => '7', # v5.16.3
110 centos => '7', # v5.16.3 (2014-07 eol 2024-06)
117 ['<code>${^LAST_FH}</code>', 'last read filehandle (used by <code>$.</code>)'],
118 ['<code>/(?[ a + b ])/</code>', 'regex set operations (character substraction <code>-</code>, unions <code>&</code>)', 'experimental::regex_sets'],
119 ['<code>my sub</code>', 'lexical subroutines (also <code>state</code>, <code>our</code>)', 'experimental::lexical_subs'],
120 ['<code>next $expression</code>', 'loop controls allow runtime expressions'],
121 [q(<code>no warnings 'experimental::…'</code>), 'mechanism for experimental features, as of now required for smartmatch'],
123 release => '2013-05-18',
129 ['<code>sub ($var)</code>', 'subroutine signatures', 'experimental::signatures'],
130 ['<code>%hash{…}</code>', 'hash slices return key+value pairs'],
131 ['<code>[]->@*</code>', 'postfix dereferencing (also e.g. <code>$scalar->$*</code> for <code>$$scalar</code>)', 'experimental::postderef'],
132 [q(<code>use warnings 'once'; $a</code>), 'variables $a and $b are exempt from <em>used once</em> warnings'],
135 release => '2014-05-27',
143 ['<code>\$alias =</code>', 'aliasing via reference'],
144 ['<code><<>></code>', 'safe readline ignoring open flags in arguments'],
145 ['<code>/()/n</code>', 'flag to disable numbered capturing, turning <code>()</code> into <code>(?:)</code>'],
148 release => '2015-01-20',