1=head1 NAME 2 3version - Perl extension for Version Objects 4 5=head1 SYNOPSIS 6 7 # Parsing version strings (decimal or dotted-decimal) 8 9 use version 0.77; # get latest bug-fixes and API 10 $ver = version->parse($string) 11 12 # Declaring a dotted-decimal $VERSION (keep on one line!) 13 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 17 18 # Declaring an old-style decimal $VERSION (use quotes!) 19 20 our $VERSION = "1.0203"; # recommended 21 use version; our $VERSION = version->parse("1.0203"); # formal 22 use version; our $VERSION = version->parse("1.02_03"); # alpha 23 24 # Comparing mixed version styles (decimals, dotted-decimals, objects) 25 26 if ( version->parse($v1) == version->parse($v2) ) { 27 # do stuff 28 } 29 30 # Sorting mixed version styles 31 32 @ordered = sort { version->parse($a) <=> version->parse($b) } @list; 33 34=head1 DESCRIPTION 35 36Version objects were added to Perl in 5.10. This module implements version 37objects for older version of Perl and provides the version object API for all 38versions of Perl. All previous releases before 0.74 are deprecated and should 39not 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 41set 0.77 as a minimum in your code, e.g. 42 43 use version 0.77; # even for Perl v.5.10.0 44 45=head1 TYPES OF VERSION OBJECTS 46 47There are two different types of version objects, corresponding to the two 48different styles of versions in use: 49 50=over 2 51 52=item Decimal Versions 53 54The classic floating-point number $VERSION. The advantage to this style is 55that you don't need to do anything special, just type a number into your 56source file. Quoting is recommended, as it ensures that trailing zeroes 57("1.50") are preserved in any warnings or other output. 58 59=item Dotted Decimal Versions 60 61The more modern form of version assignment, with 3 (or potentially more) 62integers separated by decimal points (e.g. v1.2.3). This is the form that 63Perl itself has used since 5.6.0 was released. The leading 'v' is now 64strongly recommended for clarity, and will throw a warning in a future 65release if omitted. A leading 'v' character is required to pass the 66L</is_strict()> test. 67 68=back 69 70=head1 DECLARING VERSIONS 71 72If you have a module that uses a decimal $VERSION (floating point), and you 73do not intend to ever change that, this module is not for you. There is 74nothing that version.pm gains you over a simple $VERSION assignment: 75 76 our $VERSION = "1.02"; 77 78Since Perl v5.10.0 includes the version.pm comparison logic anyways, 79you don't need to do anything at all. 80 81=head2 How to convert a module from decimal to dotted-decimal 82 83If you have used a decimal $VERSION in the past and wish to switch to a 84dotted-decimal $VERSION, then you need to make a one-time conversion to 85the new format. 86 87B<Important Note>: you must ensure that your new $VERSION is numerically 88greater than your current decimal $VERSION; this is not always obvious. First, 89convert your old decimal version (e.g. 1.02) to a normalized dotted-decimal 90form: 91 92 $ perl -Mversion -e 'print version->parse("1.02")->normal' 93 v1.20.0 94 95Then increment any of the dotted-decimal components (v1.20.1 or v1.21.0). 96 97=head2 How to C<declare()> a dotted-decimal version 98 99 use version; our $VERSION = version->declare("v1.2.3"); 100 101The C<declare()> method always creates dotted-decimal version objects. When 102used in a module, you B<must> put it on the same line as "use version" to 103ensure that $VERSION is read correctly by PAUSE and installer tools. You 104should also add 'version' to the 'configure_requires' section of your 105module metadata file. See instructions in L<ExtUtils::MakeMaker> or 106L<Module::Build> for details. 107 108B<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 110or unintentional errors on older Perls, follow these guidelines: 111 112=over 2 113 114=item * 115 116Always use a dotted-decimal with (at least) three components 117 118=item * 119 120Always use a leading-v 121 122=item * 123 124Always quote the version 125 126=back 127 128If you really insist on using version.pm with an ordinary decimal version, 129use C<parse()> instead of declare. See the L<PARSING AND COMPARING VERSIONS> 130for details. 131 132See also L<version::Internals> for more on version number conversion, 133quoting, calculated version numbers and declaring developer or "alpha" version 134numbers. 135 136=head1 PARSING AND COMPARING VERSIONS 137 138If you need to compare version numbers, but can't be sure whether they are 139expressed as numbers, strings, v-strings or version objects, then you should 140use version.pm to parse them all into objects for comparison. 141 142=head2 How to C<parse()> a version 143 144The C<parse()> method takes in anything that might be a version and returns 145a corresponding version object, doing any necessary conversion along the way. 146 147=over 2 148 149=item * 150 151Dotted-decimal: bare v-strings (v1.2.3) and strings with more than one 152decimal point and a leading 'v' ("v1.2.3"); NOTE you can technically use a 153v-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. 155 156=item * 157 158Decimal: regular decimal numbers (literal or in a string) 159 160=back 161 162Some examples: 163 164 $variable version->parse($variable) 165 --------- ------------------------- 166 1.23 v1.230.0 167 "1.23" v1.230.0 168 v1.23 v1.23.0 169 "v1.23" v1.23.0 170 "1.2.3" v1.2.3 171 "v1.2.3" v1.2.3 172 173See L<version::Internals> for more on version number conversion. 174 175=head2 How to check for a legal version string 176 177If you do not want to actually create a full blown version object, but 178would still like to verify that a given string meets the criteria to 179be parsed as a version, there are two helper functions that can be 180employed directly: 181 182=over 4 183 184=item C<is_lax()> 185 186The lax criteria corresponds to what is currently allowed by the 187version parser. All of the following formats are acceptable 188for dotted-decimal formats strings: 189 190 v1.2 191 1.2345.6 192 v1.23_4 193 1.2345 194 1.2345_01 195 196=item C<is_strict()> 197 198If you want to limit yourself to a much more narrow definition of what 199a version string constitutes, C<is_strict()> is limited to version 200strings like the following list: 201 202 v1.234.5 203 2.3456 204 205=back 206 207See L<version::Internals> for details of the regular expressions 208that define the legal version string forms, as well as how to use 209those regular expressions in your own code if C<is_lax()> and 210C<is_strict()> are not sufficient for your needs. 211 212=head2 How to compare version objects 213 214Version objects overload the C<cmp> and C<< <=> >> operators. Perl 215automatically generates all of the other comparison operators based on those 216two so all the normal logical comparisons will work. 217 218 if ( version->parse($v1) == version->parse($v2) ) { 219 # do stuff 220 } 221 222If a version object is compared against a non-version object, the non-object 223term will be converted to a version object using C<parse()>. This may give 224surprising results: 225 226 $v1 = version->parse("v0.95.0"); 227 $bool = $v1 < 0.96; # FALSE since 0.96 is v0.960.0 228 229Always comparing to a version object will help avoid surprises: 230 231 $bool = $v1 < version->parse("v0.96.0"); # TRUE 232 233Note that "alpha" version objects (where the version string contains 234a trailing underscore segment) compare as less than the equivalent 235version without an underscore: 236 237 $bool = version->parse("1.23_45") < version->parse("1.2345"); # TRUE 238 239See L<version::Internals> for more details on "alpha" versions. 240 241=head1 OBJECT METHODS 242 243=head2 is_alpha() 244 245True if and only if the version object was created with a underscore, e.g. 246 247 version->parse('1.002_03')->is_alpha; # TRUE 248 version->declare('1.2.3_4')->is_alpha; # TRUE 249 250=head2 is_qv() 251 252True only if the version object is a dotted-decimal version, e.g. 253 254 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 258 259=head2 normal() 260 261Returns a string with a standard 'normalized' dotted-decimal form with a 262leading-v and at least 3 components. 263 264 version->declare('v1.2')->normal; # v1.2.0 265 version->parse('1.2')->normal; # v1.200.0 266 267=head2 numify() 268 269Returns a value representing the object in a pure decimal form without 270trailing zeroes. 271 272 version->declare('v1.2')->numify; # 1.002 273 version->parse('1.2')->numify; # 1.2 274 275=head2 stringify() 276 277Returns a string that is as close to the original representation as possible. 278If the original representation was a numeric literal, it will be returned the 279way perl would normally represent it in a string. This method is used whenever 280a version object is interpolated into a string. 281 282 version->declare('v1.2')->stringify; # v1.2 283 version->parse('1.200')->stringify; # 1.200 284 version->parse(1.02_30)->stringify; # 1.023 285 286=head1 EXPORTED FUNCTIONS 287 288=head2 qv() 289 290This function is no longer recommended for use, but is maintained for 291compatibility with existing code. If you do not want to have it exported 292to your namespace, use this form: 293 294 use version 0.77 (); 295 296=head2 is_lax() 297 298(Not exported by default) 299 300This function takes a scalar argument and returns a boolean value indicating 301whether the argument meets the "lax" rules for a version number. Leading and 302trailing spaces are not allowed. 303 304=head2 is_strict() 305 306(Not exported by default) 307 308This function takes a scalar argument and returns a boolean value indicating 309whether the argument meets the "strict" rules for a version number. Leading 310and trailing spaces are not allowed. 311 312=head1 AUTHOR 313 314John Peacock E<lt>jpeacock@cpan.orgE<gt> 315 316=head1 SEE ALSO 317 318L<version::Internals>. 319 320L<perl>. 321 322=cut 323