JaeHyoLee's solution to Leap on the Lua track

Instructions

Test suite

Solution

Given a year, report if it is a leap year.

The tricky thing here is that a leap year in the Gregorian calendar occurs:

on every year that is evenly divisible by 4
  except every year that is evenly divisible by 100
    unless the year is also evenly divisible by 400

For example, 1997 is not a leap year, but 1996 is. 1900 is not a leap year, but 2000 is.

If your language provides a method in the standard library that does this look-up, pretend it doesn't exist and implement it yourself.

Notes

Though our exercise adopts some very simple rules, there is more to learn!

For a delightful, four minute explanation of the whole leap year phenomenon, go watch this youtube video.

Running the tests

To run the tests, run the command busted from within the exercise directory.

Further information

For more detailed information about the Lua track, including how to get help if you're having trouble, please visit the exercism.io Lua language page.

Source

JavaRanch Cattle Drive, exercise 3 http://www.javaranch.com/leap.jsp

Submitting Incomplete Solutions

It's possible to submit an incomplete solution so you can see how others have completed the exercise.

leap_spec.lua

local is_leap_year = require('leap')

describe('leap', function()
  it('a known leap year', function()
    assert.is_true(is_leap_year(1996))
  end)

  it('any old year', function()
    assert.is_false(is_leap_year(1997))
  end)

  it('turn of the 20th century', function()
    assert.is_false(is_leap_year(1900))
  end)

  it('turn of the 21st century', function()
    assert.is_true(is_leap_year(2400))
  end)
end)

return function(year)
  return year % 4 == 0 and (year % 100 ~= 0 or year % 400 == 0)
end

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JaeHyoLee's solution

to Leap in the Lua Track