3 version - Perl extension for Version Objects
7 # Parsing version strings (decimal or dotted-decimal)
9 use version 0.77; # get latest bug-fixes and API
10 $ver = version->parse($string)
12 # Declaring a dotted-decimal $VERSION (keep on one line!)
14 use version; our $VERSION = version->declare("v1.2.3"); # formal
15 use version; our $VERSION = qv("v1.2.3"); # shorthand
16 use version; our $VERSION = qv("v1.2_3"); # alpha
18 # Declaring an old-style decimal $VERSION (use quotes!)
20 our $VERSION = "1.0203"; # recommended
21 use version; our $VERSION = version->parse("1.0203"); # formal
22 use version; our $VERSION = version->parse("1.02_03"); # alpha
24 # Comparing mixed version styles (decimals, dotted-decimals, objects)
26 if ( version->parse($v1) == version->parse($v2) ) {
30 # Sorting mixed version styles
32 @ordered = sort { version->parse($a) <=> version->parse($b) } @list;
36 Version objects were added to Perl in 5.10. This module implements version
37 objects for older version of Perl and provides the version object API for all
38 versions of Perl. All previous releases before 0.74 are deprecated and should
39 not be used due to incompatible API changes. Version 0.77 introduces the new
40 'parse' and 'declare' methods to standardize usage. You are strongly urged to
41 set 0.77 as a minimum in your code, e.g.
43 use version 0.77; # even for Perl v.5.10.0
45 =head1 TYPES OF VERSION OBJECTS
47 There are two different types of version objects, corresponding to the two
48 different styles of versions in use:
52 =item Decimal Versions
54 The classic floating-point number $VERSION. The advantage to this style is
55 that you don't need to do anything special, just type a number into your
56 source file. Quoting is recommended, as it ensures that trailing zeroes
57 ("1.50") are preserved in any warnings or other output.
59 =item Dotted Decimal Versions
61 The more modern form of version assignment, with 3 (or potentially more)
62 integers separated by decimal points (e.g. v1.2.3). This is the form that
63 Perl itself has used since 5.6.0 was released. The leading 'v' is now
64 strongly recommended for clarity, and will throw a warning in a future
65 release if omitted. A leading 'v' character is required to pass the
70 =head1 DECLARING VERSIONS
72 If you have a module that uses a decimal $VERSION (floating point), and you
73 do not intend to ever change that, this module is not for you. There is
74 nothing that version.pm gains you over a simple $VERSION assignment:
76 our $VERSION = "1.02";
78 Since Perl v5.10.0 includes the version.pm comparison logic anyways,
79 you don't need to do anything at all.
81 =head2 How to convert a module from decimal to dotted-decimal
83 If you have used a decimal $VERSION in the past and wish to switch to a
84 dotted-decimal $VERSION, then you need to make a one-time conversion to
87 B<Important Note>: you must ensure that your new $VERSION is numerically
88 greater than your current decimal $VERSION; this is not always obvious. First,
89 convert your old decimal version (e.g. 1.02) to a normalized dotted-decimal
92 $ perl -Mversion -e 'print version->parse("1.02")->normal'
95 Then increment any of the dotted-decimal components (v1.20.1 or v1.21.0).
97 =head2 How to C<declare()> a dotted-decimal version
99 use version; our $VERSION = version->declare("v1.2.3");
101 The C<declare()> method always creates dotted-decimal version objects. When
102 used in a module, you B<must> put it on the same line as "use version" to
103 ensure that $VERSION is read correctly by PAUSE and installer tools. You
104 should also add 'version' to the 'configure_requires' section of your
105 module metadata file. See instructions in L<ExtUtils::MakeMaker> or
106 L<Module::Build> for details.
108 B<Important Note>: Even if you pass in what looks like a decimal number
109 ("1.2"), a dotted-decimal will be created ("v1.200.0"). To avoid confusion
110 or unintentional errors on older Perls, follow these guidelines:
116 Always use a dotted-decimal with (at least) three components
120 Always use a leading-v
124 Always quote the version
128 If you really insist on using version.pm with an ordinary decimal version,
129 use C<parse()> instead of declare. See the L<PARSING AND COMPARING VERSIONS>
132 See also L<version::Internals> for more on version number conversion,
133 quoting, calculated version numbers and declaring developer or "alpha" version
136 =head1 PARSING AND COMPARING VERSIONS
138 If you need to compare version numbers, but can't be sure whether they are
139 expressed as numbers, strings, v-strings or version objects, then you should
140 use version.pm to parse them all into objects for comparison.
142 =head2 How to C<parse()> a version
144 The C<parse()> method takes in anything that might be a version and returns
145 a corresponding version object, doing any necessary conversion along the way.
151 Dotted-decimal: bare v-strings (v1.2.3) and strings with more than one
152 decimal point and a leading 'v' ("v1.2.3"); NOTE you can technically use a
153 v-string or strings with a leading-v and only one decimal point (v1.2 or
154 "v1.2"), but you will confuse both yourself and others.
158 Decimal: regular decimal numbers (literal or in a string)
164 $variable version->parse($variable)
165 --------- -------------------------
173 See L<version::Internals> for more on version number conversion.
175 =head2 How to check for a legal version string
177 If you do not want to actually create a full blown version object, but
178 would still like to verify that a given string meets the criteria to
179 be parsed as a version, there are two helper functions that can be
186 The lax criteria corresponds to what is currently allowed by the
187 version parser. All of the following formats are acceptable
188 for dotted-decimal formats strings:
198 If you want to limit yourself to a much more narrow definition of what
199 a version string constitutes, C<is_strict()> is limited to version
200 strings like the following list:
207 See L<version::Internals> for details of the regular expressions
208 that define the legal version string forms, as well as how to use
209 those regular expressions in your own code if C<is_lax()> and
210 C<is_strict()> are not sufficient for your needs.
212 =head2 How to compare version objects
214 Version objects overload the C<cmp> and C<< <=> >> operators. Perl
215 automatically generates all of the other comparison operators based on those
216 two so all the normal logical comparisons will work.
218 if ( version->parse($v1) == version->parse($v2) ) {
222 If a version object is compared against a non-version object, the non-object
223 term will be converted to a version object using C<parse()>. This may give
226 $v1 = version->parse("v0.95.0");
227 $bool = $v1 < 0.96; # FALSE since 0.96 is v0.960.0
229 Always comparing to a version object will help avoid surprises:
231 $bool = $v1 < version->parse("v0.96.0"); # TRUE
233 Note that "alpha" version objects (where the version string contains
234 a trailing underscore segment) compare as less than the equivalent
235 version without an underscore:
237 $bool = version->parse("1.23_45") < version->parse("1.2345"); # TRUE
239 See L<version::Internals> for more details on "alpha" versions.
241 =head1 OBJECT METHODS
245 True if and only if the version object was created with a underscore, e.g.
247 version->parse('1.002_03')->is_alpha; # TRUE
248 version->declare('1.2.3_4')->is_alpha; # TRUE
252 True only if the version object is a dotted-decimal version, e.g.
254 version->parse('v1.2.0')->is_qv; # TRUE
255 version->declare('v1.2')->is_qv; # TRUE
256 qv('1.2')->is_qv; # TRUE
257 version->parse('1.2')->is_qv; # FALSE
261 Returns a string with a standard 'normalized' dotted-decimal form with a
262 leading-v and at least 3 components.
264 version->declare('v1.2')->normal; # v1.2.0
265 version->parse('1.2')->normal; # v1.200.0
269 Returns a value representing the object in a pure decimal form without
272 version->declare('v1.2')->numify; # 1.002
273 version->parse('1.2')->numify; # 1.2
277 Returns a string that is as close to the original representation as possible.
278 If the original representation was a numeric literal, it will be returned the
279 way perl would normally represent it in a string. This method is used whenever
280 a version object is interpolated into a string.
282 version->declare('v1.2')->stringify; # v1.2
283 version->parse('1.200')->stringify; # 1.200
284 version->parse(1.02_30)->stringify; # 1.023
286 =head1 EXPORTED FUNCTIONS
290 This function is no longer recommended for use, but is maintained for
291 compatibility with existing code. If you do not want to have it exported
292 to your namespace, use this form:
298 (Not exported by default)
300 This function takes a scalar argument and returns a boolean value indicating
301 whether the argument meets the "lax" rules for a version number. Leading and
302 trailing spaces are not allowed.
306 (Not exported by default)
308 This function takes a scalar argument and returns a boolean value indicating
309 whether the argument meets the "strict" rules for a version number. Leading
310 and trailing spaces are not allowed.
314 John Peacock E<lt>jpeacock@cpan.orgE<gt>
318 L<version::Internals>.