This solution does more or less the absolute minimum required by the
quiz, but it is fairly short and easy to follow, I believe. This is
my first time submitting a solution, and I’m fairly new to ruby.
Ideally, I’d like to make the class methods private, but I was having
some trouble getting that to work out. If I make them private as
things stand now, I get a no method error, “private method called” in
the constructor. I thought one could fix that by calling the class
methods without a reciever, but for some reason, when I call these
class methods without a reciever, I also get a no method error. To be
concrete, if I change the line
@string = DateRange.build_string(arr)
to
@string = build_string(arr),
when I run the unit tests below I get
NoMethodError: undefined method ‘build_string’ for :DateRange
./daterange.rb:21:in ‘initialize’
daterangetest.rb:7:in ‘test_init’
Any advice anyone could offer about how to do this
private_class_method buisiness correctly would be greatly appreciated.
– Jason M.
require ‘test/unit’
class DateRange
DAY_NUMBERS = {
1 => 'Mon',
2 => 'Tue',
3 => 'Wed',
4 => 'Thu',
5 => 'Fri',
6 => 'Sat',
7 => 'Sun'
}
# Creates a new DateRange from a list of representations of days of the
week
def initialize(*args)
# Convert the arguments to an array of day numbers
arr = args.collect {|rep| DateRange.day_num(rep)}
arr.uniq!
arr.sort!
@string = DateRange.build_string(arr)
end
# Given a sorted array of day numbers, build the string representation
def self.build_string(arr)
result = ''
while i = arr.shift
# Add the day name to the string
result << "#{DAY_NUMBERS[i]}"
# If there is a run of 3 or more consecutive days, add a '-'
character,
# and then put the last day of the run after it
if arr[1] == i + 2
result << ‘-’
i = arr.shift while arr.first == i + 1
result << “#{DAY_NUMBERS[i]}”
end
# Unless this is the last day
result << ', ' if arr.first
end
result
end
# Returns the number representation of a day of the week specified by
number,
# name, or abbreviation
#
# DateRange.day_num(2) => 2
# DateRange.day_num(‘Fri’) => 5
# DateRange.day_num(‘saturday’) => 6
def self.day_num(rep)
if (1…7).include?(rep.to_i)
rep.to_i
else
result = DAY_NUMBERS.index(rep[0,3].capitalize)
raise ArgumentError unless result
result
end
end
def to_s
@string
end
end
class DateRangeTest < Test::Unit::TestCase
def test_init
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_equal('Mon-Fri', DateRange.new(*%w(Wednesday Monday Tuesday
Thursday Friday Monday)).to_s)
assert_raise(ArgumentError) {DateRange.new(1,8)}
end
end
