Contents

require 'naturally-unicode/version'

module NaturallyUnicode
  # Perform a natural sort.
  #
  # @param [Array<String>] an_array the list of numbers to sort.
  # @return [Array<String>] the numbers sorted naturally.
  def self.sort(an_array)
    return an_array.sort_by { |x| normalize(x) }
  end

  # Convert the given number into an object that can be sorted
  # naturally. This object is an array of {NumberElement} instances.
  #
  # @param [String] number the number in complex form such as 1.2a.3.
  # @return [Array<NumberElement>] an array of NumberElements which is
  #         able to be sorted naturally via a normal 'sort'.
  def self.normalize(number)
    number.to_s.scan(%r/\p{Word}+/o).map { |i| NumberElement.new(i) }
  end

  private

  # An entity which can be compared to other like elements for
  # sorting in an array. It's an object representing
  # a value which implements the {Comparable} interface.
  class NumberElement
    include Comparable
    attr_accessor :val

    def initialize(v)
      @val = v
    end

    def <=>(other)
      if pure_integer? && other.pure_integer?
        @val.to_i <=> other.val.to_i
      elsif numbers_with_letters? || other.numbers_with_letters?
        simple_normalize(@val) <=> simple_normalize(other.val)
      elsif letters_with_numbers? || other.letters_with_numbers?
        reverse_simple_normalize(@val) <=> reverse_simple_normalize(other.val)
      else
        @val <=> other.val
      end
    end

    def pure_integer?
      @val =~ /^\d+$/
    end

    def numbers_with_letters?
      val =~ /^\d+\p{Alpha}+$/
    end

    def letters_with_numbers?
      val =~ /^\p{Alpha}+\d+$/
    end

    def simple_normalize(n)
      if n =~ /^(\d+)(\p{Alpha}+)$/
        [$1.to_i, $2]
      else
        [n.to_i]
      end
    end

    def reverse_simple_normalize(n)
      if n =~ /^(\p{Alpha}+)(\d+)$/
        [$1, $2.to_i]
      else
        [n.to_s]
      end
    end

  end
end

Version data entries

1 entries across 1 versions & 1 rubygems

Version	Path
naturally-unicode-1.1.0	lib/naturally-unicode.rb