use 5.005_03;
use strict;
+require Exporter;
require DynaLoader;
-use vars qw(@ISA $VERSION $CLASS);
+use vars qw(@ISA $VERSION $CLASS @EXPORT);
-@ISA = qw(DynaLoader);
+@ISA = qw(Exporter DynaLoader);
-$VERSION = 0.29; # stop using CVS and switch to subversion
+@EXPORT = qw(qv);
+
+$VERSION = 0.37; # stop using CVS and switch to subversion
$CLASS = 'version';
=head1 SYNOPSIS
use version;
- $version = new version "12.2.1"; # must be quoted!
+ $version = version->new("12.2.1"); # must be quoted for Perl < 5.8.1
print $version; # 12.2.1
print $version->numify; # 12.002001
- if ( $version gt "v12.2" ) # true
-
- $vstring = new version qw(v1.2); # must be quoted!
- print $vstring; # 1.2
+ if ( $version gt "12.2" ) # true
- $alphaver = new version "1.2_3"; # must be quoted!
+ $alphaver = version->new("1.2_3"); # must be quoted!
print $alphaver; # 1.2_3
print $alphaver->is_alpha(); # true
+
+ $ver = qv(1.2); # 1.2.0
+ $ver = qv("1.2"); # 1.2.0
- $perlver = new version 5.005_03; # must not be quoted!
+ $perlver = version->new(5.005_03); # must not be quoted!
print $perlver; # 5.5.30
=head1 DESCRIPTION
Overloaded version objects for all versions of Perl. This module
implements all of the features of version objects which will be part
-of Perl 5.10.0 except automatic v-string handling. See L<"Quoting">.
+of Perl 5.10.0 except automatic version object creation.
=head2 What IS a version
Any initial parameter which "looks like a number", see L<Numeric
Versions>.
-=item * V-String Versions
+=item * Quoted Versions
-Any initial parameter which contains more than one decimal point,
-contains an embedded underscore, or has a leading 'v' see L<V-String
-Versions>.
+Any initial parameter which contains more than one decimal point
+or contains an embedded underscore, see L<Quoted Versions>. The
+most recent development version of Perl (5.9.x) and the next major
+release (5.10.0) will automatically create version objects for bare
+numbers containing more than one decimal point in the appropriate
+context.
=back
Both of these methods will produce similar version objects, in that
-the default stringification will always be in a reduced form, i.e.:
+the default stringification will yield the version L<Normal Form> only
+if required:
- $v = new version 1.002003; # 1.2.3
- $v2 = new version "1.2.3"; # 1.2.3
- $v3 = new version v1.2.3; # 1.2.3 for Perl > v5.8.0
- $v4 = new version 1.2.3; # 1.2.3 for Perl > v5.8.0
+ $v = version->new(1.002); # 1.002, but compares like 1.2.0
+ $v = version->new(1.002003); # 1.2.3
+ $v2 = version->new( "1.2.3"); # 1.2.3
+ $v3 = version->new( 1.2.3); # 1.2.3 for Perl >= 5.8.1
Please see L<"Quoting"> for more details on how Perl will parse various
input values.
Any value passed to the new() operator will be parsed only so far as it
contains a numeric, decimal, or underscore character. So, for example:
- $v1 = new version "99 and 94/100 percent pure"; # $v1 == 99.0
- $v2 = new version "something"; # $v2 == "" and $v2->numify == 0
+ $v1 = version->new("99 and 94/100 percent pure"); # $v1 == 99.0
+ $v2 = version->new("something"); # $v2 == "" and $v2->numify == 0
However, see L<New Operator> for one case where non-numeric text is
acceptable when initializing version objects.
+=head2 What about v-strings?
+
+Beginning with Perl 5.6.0, an alternate method to code arbitrary strings
+of bytes was introduced, called v-strings. They were intended to be an
+easy way to enter, for example, Unicode strings (which contain two bytes
+per character). Some programs have used them to encode printer control
+characters (e.g. CRLF). They were also intended to be used for $VERSION.
+Their use has been problematic from the start and they will be phased out
+beginning in Perl 5.10.0.
+
+There are two ways to enter v-strings: a bare number with two or more
+decimal places, or a bare number with one or more decimal places and a
+leading 'v' character (also bare). For example:
+
+ $vs1 = 1.2.3; # encoded as \1\2\3
+ $vs2 = v1.2; # encoded as \1\2
+
+The first of those two syntaxes is destined to be the default way to create
+a version object in 5.10.0, whereas the second will issue a mandatory
+deprecation warning beginning at the same time. In both cases, a v-string
+encoded version will always be stringified in the version L<Normal Form>.
+
+Consequently, the use of v-strings to initialize version objects with
+this module is only possible with Perl 5.8.1 or better (which contain special
+code to enable it). Their use is B<strongly> discouraged in all
+circumstances (especially the leading 'v' style), since the meaning will
+change depending on which Perl you are running. It is better to use
+L<"Quoted Versions"> to ensure the proper interpretation.
+
=head2 Numeric Versions
-These correspond to historical versions of Perl itself prior to v5.6.0,
+These correspond to historical versions of Perl itself prior to 5.6.0,
as well as all other modules which follow the Camel rules for the
$VERSION scalar. A numeric version is initialized with what looks like
a floating point number. Leading zeros B<are> significant and trailing
zeros are implied so that a minimum of three places is maintained
between subversions. What this means is that any subversion (digits
to the right of the decimal place) that contains less than three digits
-will have trailing zeros added to make up the difference. For example:
+will have trailing zeros added to make up the difference, but only for
+purposes of comparison with other version objects. For example:
- $v = new version 1.2; # 1.200
- $v = new version 1.02; # 1.20
- $v = new version 1.002; # 1.2
- $v = new version 1.0023; # 1.2.300
- $v = new version 1.00203; # 1.2.30
- $v = new version 1.002_03; # 1.2.30 See L<"Quoting">
- $v = new version 1.002003; # 1.2.3
+ $v = version->new( 1.2); # prints 1.2, compares as 1.200.0
+ $v = version->new( 1.02); # prints 1.02, compares as 1.20.0
+ $v = version->new( 1.002); # prints 1.002, compares as 1.2.0
+ $v = version->new( 1.0023); # 1.2.300
+ $v = version->new( 1.00203); # 1.2.30
+ $v = version->new( 1.002_03); # 1.2.30 See "Quoting"
+ $v = version->new( 1.002003); # 1.2.3
All of the preceeding examples except the second to last are true
whether or not the input value is quoted. The important feature is that
the input value contains only a single decimal.
-=head2 V-String Versions
+IMPORTANT NOTE: If your numeric version contains more than 3 significant
+digits after the decimal place, it will be split on each multiple of 3, so
+1.0003 becomes 1.0.300, due to the need to remain compatible with Perl's
+own 5.005_03 == 5.5.30 interpretation.
+
+=head2 Quoted Versions
These are the newest form of versions, and correspond to Perl's own
-version style beginning with v5.6.0. Starting with Perl v5.10.0,
-this is likely to be the preferred form. This method requires that
-the input parameter be quoted, although Perl > v5.9.0 can use bare
-v-strings as a special form of quoting.
-
-Unlike L<Numeric Versions>, V-String Versions must either have more than
-a single decimal point, e.g. "5.6.1" B<or> must be prefaced by a "v"
-like this "v5.6" (much like v-string notation). In fact, with the
-newest Perl v-strings themselves can be used to initialize version
-objects. Also unlike L<Numeric Versions>, leading zeros are B<not>
-significant, and trailing zeros must be explicitely specified (i.e.
-will not be automatically added). In addition, the subversions are
-not enforced to be three decimal places.
+version style beginning with 5.6.0. Starting with Perl 5.10.0,
+and most likely Perl 6, this is likely to be the preferred form. This
+method requires that the input parameter be quoted, although Perl's after
+5.9.0 can use bare numbers with multiple decimal places as a special form
+of quoting.
+
+Unlike L<Numeric Versions>, Quoted Versions may have more than
+a single decimal point, e.g. "5.6.1" (for all versions of Perl). If a
+Quoted Version has only one decimal place (and no embedded underscore),
+it is interpreted exactly like a L<Numeric Version>.
So, for example:
- $v = new version "v1.2"; # 1.2
- $v = new version "v1.002"; # 1.2
- $v = new version "1.2.3"; # 1.2.3
- $v = new version "v1.2.3"; # 1.2.3
- $v = new version "v1.0003"; # 1.3
+ $v = version->new( "1.002"); # 1.2
+ $v = version->new( "1.2.3"); # 1.2.3
+ $v = version->new("1.0003"); # 1.0.300
-In additional to conventional versions, V-String Versions can be
+In addition to conventional versions, Quoted Versions can be
used to create L<Alpha Versions>.
-In general, V-String Versions permit the greatest amount of freedom
+In general, Quoted Versions permit the greatest amount of freedom
to specify a version, whereas Numeric Versions enforce a certain
uniformity. See also L<New Operator> for an additional method of
initializing version objects.
use the CVS variable $Revision, which is automatically incremented by
CVS every time the file is committed to the repository.
-=back
-
In order to facilitate this feature, the following
code can be employed:
- $VERSION = new version qw$Revision: 2.7 $;
+ $VERSION = version->new(qw$Revision: 2.7 $);
and the version object will be created as if the following code
were used:
- $VERSION = new version "v2.7";
+ $VERSION = version->new("v2.7");
In other words, the version will be automatically parsed out of the
string, and it will be quoted to preserve the meaning CVS normally
carries for versions.
+=back
+
+=over 4
+
+=item * qv()
+
+An alternate way to create a new version object is through the exported
+qv() sub. This is not strictly like other q? operators (like qq, qw),
+in that the only delimiters supported are parentheses (or spaces). It is
+the best way to initialize a short version without triggering the floating
+point interpretation. For example:
+
+ $v1 = qv(1.2); # 1.2.0
+ $v2 = qv("1.2"); # also 1.2.0
+
+As you can see, either a bare number or a quoted string can be used, and
+either will yield the same version number.
+
+=back
+
For the subsequent examples, the following two objects will be used:
- $ver = new version "1.2.3"; # see "Quoting" below
- $alpha = new version "1.2_3"; # see "Alpha versions" below
+ $ver = version->new("1.2.3"); # see "Quoting" below
+ $alpha = version->new("1.2_3"); # see "Alpha versions" below
+ $nver = version->new(1.2); # see "Numeric Versions" above
=over 4
-=item * Stringification
+=item * Normal Form
-Any time a version object is used as a string, a stringified
-representation is returned in reduced form (no extraneous zeros):
+For any version object which is initialized with multiple decimal
+places (either quoted or if possible v-string), or initialized using
+the L<qv()> operator, the stringified representation is returned in
+a normalized or reduced form (no extraneous zeros):
-=back
+ print $ver->normal; # prints as 1.2.3
+ print $ver->stringify; # ditto
+ print $ver; # ditto
+ print $nver->normal; # prints as 1.2.0
+ print $nver->stringify; # prints as 1.2, see "Stringification"
- print $ver->stringify; # prints 1.2.3
- print $ver; # same thing
+In order to preserve the meaning of the processed version, the
+normalized representation will always contain at least three sub terms.
+In other words, the following is guaranteed to always be true:
+
+ my $newver = version->new($ver->stringify);
+ if ($newver eq $ver ) # always true
+ {...}
+
+=back
=over 4
three decimal places. So for example:
print $ver->numify; # prints 1.002003
+ print $nver->numify; # prints 1.2
+
+Unlike the stringification operator, there is never any need to append
+trailing zeros to preserve the correct version value.
+
+=back
+
+=over 4
+
+=item * Stringification
+
+In order to mirror as much as possible the existing behavior of ordinary
+$VERSION scalars, the stringification operation will display differently,
+depending on whether the version was initialized as a L<Numeric Version>
+or L<Quoted Version>.
+
+What this means in practice is that if the normal CPAN and Camel rules are
+followed ($VERSION is a floating point number with no more than 3 decimal
+places), the stringified output will be exactly the same as the numified
+output. There will be no visible difference, although the internal
+representation will be different, and the L<Comparison operators> will
+function using the internal coding.
+
+If a version object is initialized using a L<Quoted Version> form, or if
+the number of significant decimal places exceed three, then the stringified
+form will be the L<Normal Form>. The $obj->normal operation can always be
+used to produce the L<Normal Form>, even if the version was originally a
+L<Numeric Version>.
+
+ print $ver->stringify; # prints 1.2.3
+ print $nver->stringify; # prints 1.2
+
+=back
+
+=over 4
=item * Comparison operators
generates all of the other comparison operators based on those two.
In addition to the obvious equalities listed below, appending a single
trailing 0 term does not change the value of a version for comparison
-purposes. In other words "v1.2" and "v1.2.0" are identical versions.
+purposes. In other words "v1.2" and "1.2.0" will compare as identical.
For example, the following relations hold:
$ver != 1.3 $ver ne "1.3" true
$ver == 1.2 $ver eq "1.2" false
$ver == 1.2.3 $ver eq "1.2.3" see discussion below
- $ver == v1.2.3 $ver eq "v1.2.3" ditto
-In versions of Perl prior to the 5.9.0 development releases, it is not
-permitted to use bare v-strings in either form, due to the nature of Perl's
-parsing operation. After that version (and in the stable 5.10.0 release),
-v-strings can be used with version objects without problem, see L<"Quoting">
-for more discussion of this topic. In the case of the last two lines of
-the table above, only the string comparison will be true; the numerical
-comparison will test false. However, you can do this:
+It is probably best to chose either the numeric notation or the string
+notation and stick with it, to reduce confusion. Perl6 version objects
+B<may> only support numeric comparisons. See also L<"Quoting">.
- $ver == "1.2.3" or $ver == "v1.2.3" # both true
+WARNING: Comparing version with unequal numbers of decimal places (whether
+explicitely or implicitely initialized), may yield unexpected results at
+first glance. For example, the following inequalities hold:
-even though you are doing a "numeric" comparison with a "string" value.
-It is probably best to chose either the numeric notation or the string
-notation and stick with it, to reduce confusion. See also L<"Quoting">.
+ version->new(0.96) > version->new(0.95); # 0.960.0 > 0.950.0
+ version->new("0.96.1") < version->new(0.95); # 0.096.1 < 0.950.0
+
+For this reason, it is best to use either exclusively L<Numeric Versions> or
+L<Quoted Versions> with multiple decimal places.
+
+=back
+
+=over 4
=item * Logical Operators
If you need to test whether a version object
has been initialized, you can simply test it directly:
- $vobj = new version $something;
+ $vobj = version->new($something);
if ( $vobj ) # true only if $something was non-blank
-You can also test whether a version object is a L<Alpha version>, for
+You can also test whether a version object is an L<Alpha version>, for
example to prevent the use of some feature not present in the main
release:
- $vobj = new version "1.2_3"; # MUST QUOTE
+ $vobj = version->new("1.2_3"); # MUST QUOTE
...later...
if ( $vobj->is_alpha ) # True
expect. You are pretty safe by dividing by a power of 10, for example,
but other operations are not likely to be what you intend. For example:
- $VERSION = new version (qw$Revision: 1.4)[1]/10;
+ $VERSION = version->new((qw$Revision: 1.4)[1]/10);
print $VERSION; # yields 0.14
- $V2 = new version 100/9; # Integer overflow in decimal number
- print $V2; # yields 11_1285418553
+ $V2 = version->new(100/9); # Integer overflow in decimal number
+ print $V2; # yields something like 11.111.111.100
-Perl 5.9.0 and beyond will be able to automatically quote v-strings
-(which may become the recommended notation), but that is not possible in
-earlier versions of Perl. In other words:
+Perl 5.8.1 and beyond will be able to automatically quote v-strings
+(although a warning may be issued under 5.9.x and 5.10.0), but that
+is not possible in earlier versions of Perl. In other words:
- $version = new version "v2.5.4"; # legal in all versions of Perl
- $newvers = new version v2.5.4; # legal only in Perl > 5.9.0
+ $version = version->new("v2.5.4"); # legal in all versions of Perl
+ $newvers = version->new(v2.5.4); # legal only in Perl >= 5.8.1
=head2 Types of Versions Objects
These are the versions that normal modules will use. Can contain as
many subversions as required. In particular, those using RCS/CVS can
-use one of the following:
+use the following:
- $VERSION = new version qw$Revision: 2.7 $;
+ $VERSION = version->new(qw$Revision: 2.7 $);
and the current RCS Revision for that file will be inserted
automatically. If the file has been moved to a branch, the Revision
using the Revision number from the primary file in a distribution, see
L<ExtUtils::MakeMaker/"VERSION_FROM">.
-=item * alpha versions
+=item * Alpha versions
For module authors using CPAN, the convention has been to note
unstable releases with an underscore in the version string, see
L<CPAN>. Alpha releases will test as being newer than the more recent
stable release, and less than the next stable release. For example:
- $alphaver = new version "12.3_1"; # must quote
+ $alphaver = version->new("12.3_1"); # must quote
obeys the relationship
In addition to the version objects, this modules also replaces the core
UNIVERSAL::VERSION function with one that uses version objects for its
-comparisons.
+comparisons. The return from this operator is always the numified form,
+and the warning message generated includes both the numified and normal
+forms (for clarity).
+
+For example:
+
+ package Foo;
+ $VERSION = 1.2;
+
+ package Bar;
+ $VERSION = "1.3.5"; # works with all Perl's (since it is quoted)
+
+ package main;
+ use version;
+
+ print $Foo::VERSION; # prints 1.2
+
+ print $Bar::VERSION; # prints 1.003005
+
+ eval "use CGI 10"; # some far future release
+ print $@; # prints "CGI version 10 (10.0.0) required..."
+
+IMPORTANT NOTE: This may mean that code which searches for a specific
+string (to determine whether a given module is available) may need to be
+changed.
=head1 EXPORT
-None by default.
+qv - quoted version initialization operator
=head1 AUTHOR
projects / p5sagit/p5-mst-13.2.git / blobdiff