Class: Versionable::VersionNumber

Inherits:
String
  • Object
show all
Defined in:
lib/versionable/version_number.rb

Overview

A String containing a dotted sequence of positive integers.

Constant Summary collapse

VERSION_NUMBER_REGEX = 
/^(?:0|[1-9]\d*)(?:\.(?:0|[1-9]\d*))*$/

Instance Method Summary collapse

Constructor Details

#initialize(v) ⇒ VersionNumber

Construct a VersionNumber from something that responds to #to_s.

If the to_s’d argument does not match VERSION_NUMBER_REGEX, an ArgumentError is raised.



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# File 'lib/versionable/version_number.rb', line 9

def initialize(v)
  v = v.to_s
  unless v =~ VERSION_NUMBER_REGEX
    raise ArgumentError.new "#{v.inspect} is not a dotted sequence of positive integers"
  end
  super v
end

Instance Method Details

#<=>(other) ⇒ Object

Compare version numbers as lists of integers.

If one version number has more segments than the other, the shorter one is right-extended with zeros.

For example, when comparing 0.2 to 0.10.1, the 0.2 is extended to 0.2.0. The left two 0s are equal, so comparison shifts to 2 and 10: 0.10.1 is the greater version.



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# File 'lib/versionable/version_number.rb', line 24

def <=>(other)
  my_segments, their_segments = to_s.split('.'), other.to_s.split('.')
  size_difference = my_segments.size - their_segments.size

  if size_difference > 0
    their_segments.concat(['0'] * size_difference)
  elsif size_difference < 0
    my_segments.concat(['0'] * -size_difference)
  end

  partwise = my_segments.zip(their_segments).collect do |mine, theirs|
    mine.to_i <=> theirs.to_i
  end

  partwise.detect { |cmp| cmp != 0 } || 0
end

#==(other) ⇒ Object

Test equality based on the <=> operator.

Particularly, 2 == 2.0 == 2.0.0.0



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# File 'lib/versionable/version_number.rb', line 44

def ==(other)
  (self <=> other) == 0
end

#hash ⇒ Object

Hash the version number string after stripping any trailing zeroes.

This preserves the hash/equality contract: 2 == 2.0, so they both hash the same as well.



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# File 'lib/versionable/version_number.rb', line 51

def hash
  sub(/(\.0)+$/, '').to_s.hash
end