http://search.cpan.org/~dagolden/CPAN-Meta-2.101091/lib/CPAN/Meta/Spec.pm#Comparing_Version_Numbers
is an insufficient description about how to compare version numbers. The spec
should not depend on any implementation, in this case version.pm.
A description of the algorithm of how to compare version numbers is necessary
for a complete spec. There would be four sections:
1) Comparing decimal to decimal
2) Comparing dotted to dotted
3) Comparing dotted to decimal
4) Notes about alpha versions
Decimal to Decimal
------------------
DEFINITION: Decimal versions are compared as normal decimal numbers.
EXAMPLE:
1.0 = 1.0
1.0 = 1.00
1.0 = 1
2.0 > 1.0
1.9 > 1.10
RECOMMENDATION: To avoid confusion, users are encouraged to use a fixed number
of decimal places in their versions such that comparing as numbers and
comparing as dotted pairs works the same. For example, if your first release
is 1.00 then your second should be 1.01.
Dotted to Dotted
----------------
DEFINITION: Each integer is compared as an integer with its counterpart in
sequence. If any are not equal, the comparison stops. Otherwise if all are
equal the two versions are equal. Any missing integers are treated as 0.
EXAMPLE:
v1.0.0 = v1.0.0
v1.0 = v1.0.0
v1 = v1.0.0
v1 < v1.1
v1.02 > v1.1
v2.1 > v1.9.9
NOTE: This appears to jive with version.pm
RECOMMENDATION: We recommend using at least 3 integers to avoid confusion
with decimal versions.
Dotted to Decimal
-----------------
RECOMMENDATION: To avoid confusion, when changing between dotted and decimal
versions, it is recommend you increment the first integer. 1.09 should be
followed by 2.0.0.
DEFINITION:
When comparing dotted version numbers with decimal version numbers, the
decimal is first converted to a dotted version. Then they are compared as
dotted versions.
1) The decimal part is multiplied by 1000.
2) The result is treated as the next integer.
2a) If the result is a decimal, goto 1.
3) Alpha versions are left alone.
EXAMPLE:
1.02 -> v1.20.0
1.2 -> v1.200.0
1.2001 -> v1.200.100
1.02_01 -> v1.20.0_01
NOTE: This appears to jive with version.pm
Notes about alpha versions
--------------------------
DEFINITION:
1) Strip off the alpha version
2) If they are equal, the alpha version is the lesser.
2b) If they are both alphas, compare the alpha numbers as integers
3) If they are not, compare normally.
EXAMPLE:
1.00_01 < 1.00
v1.0.0_01 < v1
1.00_00 < 1.00
1.01_01 > 1.00
1.00_01 = 1.00_01
1.00_02 > 1.00_01
RECOMMENDATION: To avoid confusion, increment your version number between an
alpha release and stable. That is, 1.2.3_1 should be followed by 1.2.4.
NOTE: This doesn't appear to jive with version.pm. Here's what it does:
1.0100 < 1.0101_01
1.0101 > 1.0101_00
1.0101 < 1.0101_01
IMO X.Y_Z should always be < than X.Y. That is, 1.01 > 1.01_05. This reads
1.01_05 as "the 5th alpha release of 1.01" just like Firefox 3.6.4 beta 1 will
eventually be followed by Firefox 3.6.4.
--
40. I do not have super-powers.
-- The 213 Things Skippy Is No Longer Allowed To Do In The U.S. Army
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