Please Forward: Ruby Quiz Submission

ruby-talk
1

From: "Mathias Kegelmann" <mathias.kegelmann@sdm.de>
Date: August 27, 2006 7:02:19 PM CDT
To: submission@rubyquiz.com
Cc: mathias.kegelmann@sdm.de
Subject: Please Forward: Ruby Quiz Submission

Hello,

here's my solution (and also my first submission to RubyQuiz):

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#
# 92-DateRange.rb
#

module Enumerable
  # Divide the Enumerable into arrays of "runs". A run is a sequence of
  # consecutive elements, in the sense of "succ".
  # If a block is given, then the methods acts as an iterator,
  # otherwise it returns an array of run arrays.
  def runs
    unless block_given?
      a =
      runs { |x| a << x }
      return a
    end

    current =
    each do |x|
      if current.empty? || current.last.succ == x
        current << x
      else
        yield current
        current =
      end
    end
    yield current unless current.empty?
  end
end

class DateRange
  @@days = %w{Monday Tuesday Wednesday Thursday Friday Saturday Sunday}
  @@map = { }
  @@days.each_with_index do |d, i|
    i += 1
    @@map[d] = i
    @@map[d[0...3]] = i
    @@map[i] = i
  end

  def self.day_to_i(day)
    raise ArgumentError.new(day.to_s) unless result = @@map[day]
    return result
  end

  def self.i_to_s(n)
    raise ArgumentError.new(n.to_s) unless (1..7) === n
    @@days[n - 1][0...3]
  end

  def initialize(*days)
    @days = days.collect{|d| DateRange.day_to_i(d)}.sort.uniq
  end

  def to_s
    @days.runs.collect do |a|
      from = DateRange.i_to_s(a.first)
      till = DateRange.i_to_s(a.last)
      case a.size
      when 1 then from
      when 2 then from + ", " + till
      else from + "-" + till
      end
    end.join(", ")
  end

end

----------------------------------------------------------------------

Here are the unit tests:

----------------------------------------------------------------------

#
# 92-test.rb
#

require 'test/unit'
require '92-DateRange'

class DateRangeTest < Test::Unit::TestCase

  def test_runs
    assert_equal , .runs
    assert_equal [[1]], [1].runs
    assert_equal [[1,2]], [1,2].runs
    assert_equal [[1],[3]], [1,3].runs
    assert_equal [[1,2,3],[5],[3,4],[2]], [1,2,3,5,3,4,2].runs
  end

  def test_day_to_i
    assert_equal 1, DateRange.day_to_i(1)
    assert_equal 2, DateRange.day_to_i("Tuesday")
    assert_equal 3, DateRange.day_to_i("Wed")
    assert_equal 4, DateRange.day_to_i(4)
    assert_equal 5, DateRange.day_to_i("Friday")
    assert_equal 6, DateRange.day_to_i("Sat")
    assert_equal 7, DateRange.day_to_i("Sunday")
    assert_raise(ArgumentError) { DateRange.day_to_i("Hello") }
    assert_raise(ArgumentError) { DateRange.day_to_i(0) }
    assert_raise(ArgumentError) { DateRange.day_to_i(8) }
  end

  def test_i_to_s
    assert_equal "Mon", DateRange.i_to_s(1)
    assert_equal "Tue", DateRange.i_to_s(2)
    assert_equal "Wed", DateRange.i_to_s(3)
    assert_equal "Thu", DateRange.i_to_s(4)
    assert_equal "Fri", DateRange.i_to_s(5)
    assert_equal "Sat", DateRange.i_to_s(6)
    assert_equal "Sun", DateRange.i_to_s(7)
    assert_raise(ArgumentError) { DateRange.i_to_s(0) }
    assert_raise(ArgumentError) { DateRange.i_to_s(8) }
  end

  def test_date_range
    assert_equal "", DateRange.new().to_s
    assert_equal "Mon", DateRange.new(1).to_s
    assert_equal "Mon, Tue", DateRange.new(1,2).to_s
  end

  def test_quiz_cases
    assert_equal "Mon-Sun", DateRange.new(1,2,3,4,5,6,7).to_s
    assert_equal "Mon-Wed, Sat, Sun", DateRange.new(1,2,3,6,7).to_s
    assert_equal "Mon, Wed-Sat", DateRange.new(1,3,4,5,6).to_s
    assert_equal "Tue-Thu, Sat, Sun", DateRange.new(2,3,4,6,7).to_s
    assert_equal "Mon, Wed, Thu, Sat, Sun", DateRange.new(1,3,4,6,7).to_s
    assert_equal "Sun", DateRange.new(7).to_s
    assert_equal "Mon, Sun", DateRange.new(1,7).to_s
    assert_raise(ArgumentError) { DateRange.new(1,8).to_s }
  end

end

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Cheers,
Mathias

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