version(3p) Perl Programmers Reference Guide version(3p) #
version(3p) Perl Programmers Reference Guide version(3p)
NNAAMMEE #
version - Perl extension for Version Objects
SSYYNNOOPPSSIISS #
# Parsing version strings (decimal or dotted-decimal)
use version 0.77; # get latest bug-fixes and API
$ver = version->parse($string)
# Declaring a dotted-decimal $VERSION (keep on one line!)
use version; our $VERSION = version->declare("v1.2.3"); # formal
use version; our $VERSION = qv("v1.2.3"); # deprecated
use version; our $VERSION = qv("v1.2_3"); # deprecated
# Declaring an old-style decimal $VERSION (use quotes!)
our $VERSION = "1.0203"; # recommended
use version; our $VERSION = version->parse("1.0203"); # formal
use version; our $VERSION = version->parse("1.02_03"); # alpha
# Comparing mixed version styles (decimals, dotted-decimals, objects)
if ( version->parse($v1) == version->parse($v2) ) {
# do stuff
}
# Sorting mixed version styles
@ordered = sort { version->parse($a) <=> version->parse($b) } @list;
DDEESSCCRRIIPPTTIIOONN #
Version objects were added to Perl in 5.10. This module implements
version objects for older version of Perl and provides the version object
API for all versions of Perl. All previous releases before 0.74 are
deprecated and should not be used due to incompatible API changes.
Version 0.77 introduces the new 'parse' and 'declare' methods to
standardize usage. You are strongly urged to set 0.77 as a minimum in
your code, e.g.
use version 0.77; # even for Perl v.5.10.0
TTYYPPEESS OOFF VVEERRSSIIOONN OOBBJJEECCTTSS #
There are two different types of version objects, corresponding to the
two different styles of versions in use:
Decimal Versions
The classic floating-point number $VERSION. The advantage to this
style is that you don't need to do anything special, just type a number
into your source file. Quoting is recommended, as it ensures that
trailing zeroes ("1.50") are preserved in any warnings or other output.
Dotted Decimal Versions
The more modern form of version assignment, with 3 (or potentially
more) integers separated by decimal points (e.g. v1.2.3). This is the
form that Perl itself has used since 5.6.0 was released. The leading
'v' is now strongly recommended for clarity, and will throw a warning
in a future release if omitted. A leading 'v' character is required to
pass the "iiss__ssttrriicctt(())" test.
DDEECCLLAARRIINNGG VVEERRSSIIOONNSS #
If you have a module that uses a decimal $VERSION (floating point), and
you do not intend to ever change that, this module is not for you. There
is nothing that version.pm gains you over a simple $VERSION assignment:
our $VERSION = "1.02";
Since Perl v5.10.0 includes the version.pm comparison logic anyways, you
don't need to do anything at all.
HHooww ttoo ccoonnvveerrtt aa mmoodduullee ffrroomm ddeecciimmaall ttoo ddootttteedd--ddeecciimmaall If you have used a decimal $VERSION in the past and wish to switch to a dotted-decimal $VERSION, then you need to make a one-time conversion to the new format.
IImmppoorrttaanntt NNoottee: you must ensure that your new $VERSION is numerically
greater than your current decimal $VERSION; this is not always obvious.
First, convert your old decimal version (e.g. 1.02) to a normalized
dotted-decimal form:
$ perl -Mversion -e 'print version->parse("1.02")->normal'
v1.20.0
Then increment any of the dotted-decimal components (v1.20.1 or v1.21.0).
HHooww ttoo “"ddeeccllaarree(())“” aa ddootttteedd--ddeecciimmaall vveerrssiioonn use version; our $VERSION = version->declare(“v1.2.3”);
The "declare()" method always creates dotted-decimal version objects.
When used in a module, you mmuusstt put it on the same line as "use version"
to ensure that $VERSION is read correctly by PAUSE and installer tools.
You should also add 'version' to the 'configure_requires' section of your
module metadata file. See instructions in ExtUtils::MakeMaker or
Module::Build for details.
IImmppoorrttaanntt NNoottee: Even if you pass in what looks like a decimal number
("1.2"), a dotted-decimal will be created ("v1.200.0"). To avoid
confusion or unintentional errors on older Perls, follow these
guidelines:
• Always use a dotted-decimal with (at least) three components
• Always use a leading-v
• Always quote the version
If you really insist on using version.pm with an ordinary decimal
version, use "parse()" instead of declare. See the "PARSING AND
COMPARING VERSIONS" for details.
See also version::Internals for more on version number conversion,
quoting, calculated version numbers and declaring developer or "alpha"
version numbers.
PPAARRSSIINNGG AANNDD CCOOMMPPAARRIINNGG VVEERRSSIIOONNSS #
If you need to compare version numbers, but can't be sure whether they
are expressed as numbers, strings, v-strings or version objects, then
you should use version.pm to parse them all into objects for comparison.
HHooww ttoo “"ppaarrssee(())“” aa vveerrssiioonn The “parse()” method takes in anything that might be a version and returns a corresponding version object, doing any necessary conversion along the way.
• Dotted-decimal: bare v-strings (v1.2.3) and strings with more than one
decimal point and a leading 'v' ("v1.2.3"); NOTE you can technically
use a v-string or strings with a leading-v and only one decimal point
(v1.2 or "v1.2"), but you will confuse both yourself and others.
• Decimal: regular decimal numbers (literal or in a string)
Some examples:
$variable version->parse($variable)
--------- -------------------------
1.23 v1.230.0
"1.23" v1.230.0
v1.23 v1.23.0
"v1.23" v1.23.0
"1.2.3" v1.2.3
"v1.2.3" v1.2.3
See version::Internals for more on version number conversion.
HHooww ttoo cchheecckk ffoorr aa lleeggaall vveerrssiioonn ssttrriinngg If you do not want to actually create a full blown version object, but would still like to verify that a given string meets the criteria to be parsed as a version, there are two helper functions that can be employed directly:
"is_lax()"
The lax criteria corresponds to what is currently allowed by the
version parser. All of the following formats are acceptable for
dotted-decimal formats strings:
v1.2
1.2345.6
v1.23_4
1.2345
1.2345_01
"is_strict()"
If you want to limit yourself to a much more narrow definition of
what a version string constitutes, "is_strict()" is limited to
version strings like the following list:
v1.234.5
2.3456
See version::Internals for details of the regular expressions that define
the legal version string forms, as well as how to use those regular
expressions in your own code if "is_lax()" and "is_strict()" are not
sufficient for your needs.
HHooww ttoo ccoommppaarree vveerrssiioonn oobbjjeeccttss Version objects overload the “cmp” and “<=>” operators. Perl automatically generates all of the other comparison operators based on those two so all the normal logical comparisons will work.
if ( version->parse($v1) == version->parse($v2) ) {
# do stuff
}
If a version object is compared against a non-version object, the non-
object term will be converted to a version object using "parse()". This
may give surprising results:
$v1 = version->parse("v0.95.0");
$bool = $v1 < 0.94; # TRUE since 0.94 is v0.940.0
Always comparing to a version object will help avoid surprises:
$bool = $v1 < version->parse("v0.94.0"); # FALSE
Note that "alpha" version objects (where the version string contains a
trailing underscore segment) compare as less than the equivalent version
without an underscore:
$bool = version->parse("1.23_45") < version->parse("1.2345"); # TRUE
See version::Internals for more details on "alpha" versions.
OOBBJJEECCTT MMEETTHHOODDSS #
iiss__aallpphhaa(()) True if and only if the version object was created with a underscore, e.g.
version->parse('1.002_03')->is_alpha; # TRUE
version->declare('1.2.3_4')->is_alpha; # TRUE
iiss__qqvv(()) True only if the version object is a dotted-decimal version, e.g.
version->parse('v1.2.0')->is_qv; # TRUE
version->declare('v1.2')->is_qv; # TRUE
qv('1.2')->is_qv; # TRUE
version->parse('1.2')->is_qv; # FALSE
nnoorrmmaall(()) Returns a string with a standard ’normalized’ dotted-decimal form with a leading-v and at least 3 components.
version->declare('v1.2')->normal; # v1.2.0
version->parse('1.2')->normal; # v1.200.0
nnuummiiffyy(()) Returns a value representing the object in a pure decimal.
version->declare('v1.2')->numify; # 1.002000
version->parse('1.2')->numify; # 1.200
ssttrriinnggiiffyy(()) Returns a string that is as close to the original representation as possible. If the original representation was a numeric literal, it will be returned the way perl would normally represent it in a string. This method is used whenever a version object is interpolated into a string.
version->declare('v1.2')->stringify; # v1.2
version->parse('1.200')->stringify; # 1.2
version->parse(1.02_30)->stringify; # 1.023
EEXXPPOORRTTEEDD FFUUNNCCTTIIOONNSS #
qqvv(()) This function is no longer recommended for use, but is maintained for compatibility with existing code. If you do not want to have it exported to your namespace, use this form:
use version 0.77 ();
iiss__llaaxx(()) (Not exported by default)
This function takes a scalar argument and returns a boolean value
indicating whether the argument meets the "lax" rules for a version
number. Leading and trailing spaces are not allowed.
iiss__ssttrriicctt(()) (Not exported by default)
This function takes a scalar argument and returns a boolean value
indicating whether the argument meets the "strict" rules for a version
number. Leading and trailing spaces are not allowed.
AAUUTTHHOORR #
John Peacock <jpeacock@cpan.org>
SSEEEE AALLSSOO #
version::Internals.
perl.
perl v5.36.3 2023-02-15 version(3p)