+
+ v5.20 => {
+ new => [
+ ['<code>sub ($var)</code>', 'subroutine signatures', {feature => 'signatures', experimental => 'signatures'}],
+ ['<code>%hash{…}</code>', 'hash slices return key+value pairs'],
+ ['<code>[]->@*</code>', 'postfix dereferencing (also e.g. <code>$scalar->$*</code> for <code>$$scalar</code>)', {feature => 'postderef, postderef_qq', experimental => 'postderef', stable => v5.23.1}],
+ [q"<code>use warnings 'once'; $a</code>", 'variables $a and $b are exempt from <em>used once</em> warnings'],
+ ],
+ unicode => '6.3',
+ release => '2014-05-27',
+ distro => {
+ debian => 'jessie',
+ ubuntu => '14.10',
+ aix => '7.2',
+ },
+ },
+
+ v5.22 => {
+ new => [
+ ['<code>\$alias =</code>', 'aliasing via reference (scoped as of v5.25.3)', {experimental => 'refaliasing'}],
+ ['<code><<>></code>', 'safe <code>readline</code> ignoring open flags in arguments'],
+ ['<code>/()/n</code>', 'flag to disable numbered capturing, turning <code>()</code> into <code>(?:)</code>'],
+ ['<code>/\b{}/</code>', 'boundary types: <em>gcb</em> (grapheme cluster), <em>sb</em> (sentence), <em>wb</em> (word)'],
+ ['<code>&.</code>', '<code>& | ^ ~</code> consistently numeric, dotted operators for strings', {experimental => 'bitwise'}],
+ [q"<code>use re 'strict'</code>", 'apply stricter syntax rules to regular expression patterns', {experimental => 're_strict'}],
+ ['<code>0x.beep+0</code>', q"hexadecimal floating point notation with binary power; <code>printf '%a'</code> to display"],
+ ],
+ unicode => '7.0',
+ release => '2015-06-01',
+ distro => {
+ ubuntu => '16.04',
+ },
+ },
+
+ v5.24 => {
+ new => [
+ [q"<code>printf '%.*2$x'</code>", 'reordered precision arguments'],
+ ['<code>/\b{lb}/</code>', 'line break boundary type (position suitable for hyphenation)'],
+ ['<code>/faster/</code>', 'various significant speedups, notably matching fixed substrings, <code>/i</code> on caseless languages, 64-bit arithmetic, scope overhead'],
+ ],
+ unicode => '8.0',
+ release => '2016-05-09',
+ },
+
+ v5.25.10 => {
+ new => [
+ ['<code><<~EOT</code>', 'indented here-docs, strips same whitespace before delimiter in each line'],
+ ['<code>@{^CAPTURE}</code>', q"array of last match's captures, so <code>${^CAPTURE}[0]</code> is <code>$1</code>"],
+ ['<code>//xx</code>', 'extended modifier to also ignore whitespace in bracketed character classes'],
+ ],
+ unicode => '9.0', # also Script_Extensions/scx in "\p{script}"
+ release => '2017-02-20',
+ },