Perl release summary
The most significant features introduced for recent versions of the Perl
scripting language.
Core security support is provided for 3 years, so typical users should run at least 5.36.
Stable distributions such as Debian 11 maintain 5.32+.
Enterprise platforms retain versions up to 5.10.
5.40 2024-06-09: latest stable release
use v5.40
- import builtin functions and enable the try feature
__CLASS__
- keyword to reference to the current class name, similar to
__PACKAGE__
(feature)
:reader
- attribute for field variables to create corresponding accessor methods (feature)
^^
- higher precedence logical
xor
operator, as ||
is to or
builtin::inf
, builtin::nan
- constants equivalent to special floating point values infinity and Not a Number
use Test2::Suite
- comprehensive set of test tools for writing unit tests, providing a drop in replacement to
Test::More
5.38 2023-07-02: active core support
use feature "module_true"
- packages implicitly return true, enabled along with
no feature "bareword_filehandles"
(bundled)
sub ($var ||=
default)
- assign values when false (or undefined on
//=
) instead of omitted
/(*{ … })/
- optimistic eval:
(?{ … })
with regex optimisations enabled
class
- define object classes: packages with
field
variables and method
subroutines (feature, experimental)
${^LAST_SUCCESSFUL_PATTERN}
- explicit variable to access the previous match as in
s//…/
%{^HOOK}
- perform tasks
require__before
and require__after
when calling require
- Unicode
- v15.0
5.36 2022-05-28: official security patches
use v5.36
- use
warnings
; use feature qw'signatures isa
'; no feature qw'indirect multidimensional switch
'
use builtin
- namespace for interpreter functions, such as
weaken
and blessed
from Scalar::Util
, ceil
/floor
from POSIX
, and trim
like String::Util
(experimental until 5.40 then bundled)
is_bool(!0)
- distinguish scalar variable types (by
builtin
functions) for data interoperability
for my ($k, $v) (%hash)
- iterate over multiple values at a time (including
builtin::indexed
for arrays) (feature, experimental until 5.40)
defer {}
- queue code to be executed when going out of scope (feature, experimental)
try {} finally {}
- run code at the end of a
try
construct regardless of failure (feature, experimental)
- unicode delimiters for quoting operators (experimental)
sub ($var) {!pop}
- signatured subs are stable, but mixing with the arguments array
@_
remains experimental (feature, experimental)
$SIG{FPE}
- floating-point exceptions no longer deferred but delivered immediately like other signals
- perl
-g
- disable input record separator (slurp mode), alias for
-0777
- Unicode
- v14.0
5.34 2021-05-20
try {} catch
- exception handling similar to eval blocks (feature, experimental until 5.40 then bundled)
/{,n}/
- empty lower bound quantifier is accepted as shorthand for 0
\x{ … }
- insignificant space within curly braces, also for
\b{}
, \g{}
, \k{}
, \N{}
, \o{}
as well as /{m,n}/
quantifiers
0o0
- octal prefix
0o
alternative to 0…
and oct
re::optimization(qr//)
- debug regular expression optimization information discovered at compile time
no feature …
- disable discouraged practices of
multidimensional
and bareword_filehandles
array emulation (bundled in 5.36 and 5.38)
5.32 2020-06-20: still maintained by common vendors
isa
- infix operator to check class instance (feature, experimental until 5.36 then bundled)
$min < $_ <= $max
- chained comparison repeats inner part as
$min < $_ and $_ <= $max
/\p{Name=$var}/
- match Unicode Name property like
\N{}
but with interpolation and subpatterns
open F, '+>>', undef
- respect append mode on temporary files with mixed access
no feature 'indirect'
- disable indirect object notation such as
new Class
instead of Class->new
(bundled in 5.36)
- streamzip
- program distributed with core IO::Compress::Base to compress stdin into a zip container
- Unicode
- v13.0
5.30 2019-05-22
/(?<=var+)
- variable length lookbehind assertions (experimental until 5.36)
m(\p{nv=/.*/})
- match unicode properties by regular expressions (experimental)
my $state if 0
- workaround for
state
(deprecated since v5.10!) is now prohibited
qr'\N'
- Delimiters must be graphemes; unescaped
{
illegal; \N
in single quotes
- Unicode
- v12.1
5.28 2018-06-22
delete %hash{…}
- hash slices can be deleted with key+value pairs
/(*…)/
- alphabetic synonyms for assertions, e.g.
(*atomic:…)
for (?>…)
and (*nlb:…)
for (?<!…)
(experimental until 5.31.6)
/(*script_run:)/
- enforces all characters to be from the same script (experimental until 5.31.6)
state @a
- persistent lexical array or hash variables (in addition to scalars)
- perl
-i -pe die
- safe in-place editing: files are replaced only after successful completion
${^SAFE_LOCALES}
- locales are thread-safe on supported systems, indicated by this variable
- Unicode
- v10.0
5.26 2017-05-30
use lib '.'
- current directory no longer included in default module search path
@INC
<<~EOT
- indented here-docs, strips same whitespace before delimiter in each line
@{^CAPTURE}
- array of last match's captures, so
${^CAPTURE}[0]
is $1
//xx
- extended modifier to also ignore whitespace in bracketed character classes
use Test2::V0
- generic testing framework to replace
Test::*
and TAP::*
- Unicode
- v9.0
5.24 2016-05-09
printf '%.*2$x'
- reordered precision arguments
/\b{lb}/
- line break boundary type (position suitable for hyphenation)
/faster/
- various significant speedups, notably matching fixed substrings,
/i
on caseless languages, 64-bit arithmetic, scope overhead
- Unicode
- v8.0
5.22 2015-06-01
\$alias =
- aliasing via reference (scoped as of v5.25.3) (experimental)
<<…>>
- safe
readline
ignoring open flags in arguments
/()/n
- flag to disable numbered capturing, turning
()
into (?:)
/\b{}/
- boundary types: gcb (grapheme cluster), sb (sentence), wb (word)
&.
& | ^ ~
consistently numeric, dotted operators for strings (feature, experimental until 5.28 then bundled)
use re 'strict'
- apply stricter syntax rules to regular expression patterns (experimental)
0x.beep+0
- hexadecimal floating point notation with binary power;
printf '%a'
to display
??
- single match shorthand (deprecated since v5.14) requires the operator
m?PATTERN?
use CGI
- deprecated interface for serving http requests removed from core, see CGI::Alternatives
- Unicode
- v7.0
5.20 2014-05-27: extended vendor support 202X
sub ($var)
- subroutine signatures (feature, experimental until 5.36 then bundled)
%hash{…}
- hash slices return key+value pairs
[]->@*
- postfix dereferencing (also e.g.
$scalar->$*
for $$scalar
) (feature, experimental until 5.24 then bundled)
use warnings 'once'; $a
- variables $a and $b are exempt from used once warnings
- Unicode
- v6.3
5.18 2013-05-18
- PERL_PERTURB_KEYS=1
- hash overhaul; order is randomised instead of being semi-repeatable {
each %{{%hash}} ne each %{{%hash}}
}
${^LAST_FH}
- last read filehandle (used by
$.
)
/(?[ a + b ])/
- regex set operations (character subtraction
-
, union +
, intersection &
, xor ^
) (experimental until 5.36)
my sub
- lexical subroutines (also
state
, our
); buggy before v5.22 (experimental until 5.26)
next $expression
- loop controls allow runtime expressions
no warnings 'experimental::…'
- mechanism for experimental features, as of now required for smartmatch
- Unicode
- v6.2
5.16 2012-05-20
__SUB__
- current subroutine reference (feature, bundled)
fc, "\F"
- unicode foldcase to compare case-insensitively (feature, bundled)
"\N{}"
- automatic
use charnames qw( :full :short )
- Unicode
- v6.1
5.14 2011-05-14
s///r
- non-destructive substitution
/(?{ m() })/
- regular expressions can be nested in
/(?{})/
and /(??{})/
(experimental until 5.20)
/dalu
- regexp modifiers to restrict character classes: either default, ascii, locale, or unicode semantics.
use re '/flags'
- customise default modifiers
/(?^)/
- construct to reset to default modifiers
FH->method
- filehandle method calls load IO::File on demand (eg.
STDOUT->flush
)
\o{}
- escape sequence for octal values beyond 0777
package {}
- package declaration in scope of code block only
multiple: labels:
- statement labels allowed in all places, even before other labels
use JSON
- interface with data in JavaScript Object Notation {
decode_json <>
}
- Unicode
- v6.0+#8
5.12 2010-04-12
package
versionpackage
NAME VERSION shorthand for our $VERSION
...
- yada-yada operator: code placeholder
use 5.012
- implicit
strict
if use VERSION >= v5.12
… when
when
is now allowed to be used as a statement modifier
use overload 'qr'
- customisable conversion to regular expressions
/\N/
- inverse \n to match any character except newline regardless of
/s
(experimental until 5.18)
- Unicode
- v5.2
5.10 2007-12-18: supported commercially until 2024
use v5.10
- minimal perl version with bundled features (pragma to lexically enable backwards-incompatible syntax)
//
- defined-or operator
~~
- smart-match operator to compare different data types (updated in v5.10.1) (experimental)
say
- print with newline, equivalent to
print @_, "\n"
(feature, bundled)
given
- switch statement to smart-match with
when
/default
(feature, experimental, bundled)
/(?<name>)/
- named capture buffers into
%+
/(?1)/
- recursive regular expression patterns
/(?|)/
- resets capture numbering for each contained branch
/.++/
- possessive quantifiers
?+
, *+
, ++
to match greedily
s/keep\K//
- floating positive lookbehind, efficient alternative for
s/(keep)/$1/
/p
- optionally preserve
${^MATCH}
variables (avoiding $&
penalty until COW in v5.20)
/\v/, /\h/
- vertical and horizontal whitespace escapes (
\V
\H
to invert); also /\R/
for newlines
state
- persistent
my
variables (scalars only until 5.28) (feature, bundled)
use autodie
- replace builtin functions to throw exceptions instead of returning failure {
eval {open ...} or $@->matches("open") || die
}
use IO::Compress::Zip
- various file compression standards {
zip IO::Uncompress::Gunzip
->new("test.gz")
=> "recompressed.zip"
}
use Time::Piece
- timestamps as objects {
localtime->year > 1900
}
use File::Fetch
- generic data retrieval/download {
File::Fetch->new(uri => "http://localhost/")
->fetch(to => \$slurp)
}
- Unicode
- v5.0.0
5.8 2002-07-18: stable minimum upto 2021
no utf8
- full unicode support,
utf8
pragma only for script encoding
use open
- file handle behaviour altered by PerlIO layers {
binmode $fh, ":bytes"
}
open $fh, '-|', @cmd
- open list to fork a command without spawning a shell
open $fh, '>', \$var
- perl scalars as virtual files
printf '%1$s', @args
- syntax to use parameters out of order
1_2_3 == 123
- underscores between digits allowed in numeric constants
use bignum
- transparent big number support {
length 1e100 == 101
}
use if
- conditional module inclusion {
no if $] >= 5.022, "warnings", "redundant"
}
use Digest
- calculate various message digests (data hashes) {
$hash = sha256_hex($data)
}
use Encode
- character set conversion {
encode("utf8", decode("iso-8859-1", $octets))
}
use File::Temp
- create a temporary file or directory safely {
$fh = tempfile();
}
use List::Util
- general-utility list subroutines {
@cards = shuffle 0..51
}
use Locale::Maketext
- various localization and internationalization in
Locale::*
and L18N::*
use Memoize
- remember function results, trading space for time {
memoize "stat"
}
use MIME::Base64
- base64 encoded strings as in email attachments
use Test::More
- modern framework for unit testing {
is $got, $expected
}
use Time::HiRes
- high resolution timers {
$μs = [gettimeofday]; sleep .1;
$elapsed = tv_interval $μs
}
- Unicode
- v3.2.0
5.6 2000-03-23: start of modern compatibility
use warnings
- pragma to enable warnings in lexical scope
use utf8
- experimental unicode semantics (completed in v5.8) (experimental until 5.8)
use charnames
- string escape
\N{}
to insert named character
our
- declare global variables
v1.2.3
- represent strings as vector of ordinals, useful in version numbers (
printf '%vd'
to display)
0b0
- binary numbers in literals,
printf '%b'
, and oct
sub :lvalue
- subroutine attribute to return a modifiable value (experimental until 5.20)
open my $fh, $mode, $expr
- file handles in scoped scalars, third argument for unambiguous file name
pack 'q'
- 64-bit integer support (also large files >2GiB) (experimental until 5.8.1)
sort $coderef ()
- comparison function can be a subroutine reference; prototype
($$)
to pass elements as normal @_
CHECK {}
- special block called at end of compilation
/[[:…:]]/
- POSIX character class syntax such as
/[[:alpha:]]/
- Unicode
- v3.0.1