[Soks] Rounding error?

[Bil Kleb]

 > On 3 Mar 2005, at 16:02, Bil Kleb wrote:
 >>  It has been changed 22 time(s) (roughly once every 0 days).

Tom Counsell wrote:
> True.  Design mistake on my part.  Was going to make it shift units to 
> hours, minutes and seconds, but hadn't got round to that. 

FWIW, here's what I ended up hacking in:

# extended the Numeric class in start.rb:

class Numeric
  # similar to  distance_of_time_in_words as found in
  # actionpack-1.1.0/lib/action_view/helpers/date_helper.rb
  def to_time_units
   seconds = self.round
   case seconds
    when 0:                                "fraction of a second"
    when 1:                                "second"
    when 2..45:                            "#{seconds} seconds"
    when 46..90:                           "minute"
    when 91..(60*45):                      "#{(seconds.to_f/60.0).round} minutes"
    when (60*45)..(60*90):                 "hour"
    when (60*90)..(60*60*22):              "#{(seconds.to_f/60.0/60.0).round} hours"
    when (60*60*22)..(60*60*36):           "day"
    when (60*60*36)..(60*60*24*26):        "#{(seconds.to_f/60.0/60.0/24.0).round} days"
    when (60*60*24*26)..(60*60*24*45):     "month"
    when (60*60*24*45)..(60*60*24*30*11):  "#{(seconds.to_f/60.0/60.0/24.0/30.0).round} months"
    when (60*60*24*30*11)..(60*60*24*500): "year"
   else                                    "#{(seconds.to_f/60.0/60.0/24.0/365.0).round} years"
   end
  end
end

Note: I originally tried to stick the above directly in
@view/Page_meta.rhtml@ but I ran into syntax errors and
quickly abandoned the attempt because I don't fully
grok ERB yet.


# changed the relevant portion of @view/Page_meta.rhtml@ to

<% seconds_per_change = (Time.now-page.created_on)/page.revisions.size.to_i %>

<p>
It has been changed
<%= page.revisions.size %> time<%= page.revisions.size == 1 ? '' : 's' %>
(roughly once every <%= seconds_per_change.to_time_units %>).
</p>

Regards,
--
Bil Kleb
http://fun3d.larc.nasa.gov


Of course, the above Numeric extension was developed test-first:

require 'test/unit'

class ToTimeUnitsMT < Test::Unit::TestCase
  def test_seconds
   assert_equal( 'fraction of a second', 0.4.to_time_units )
   assert_equal( 'second', 0.8.to_time_units )
   assert_equal( 'second', 1.3.to_time_units )
   assert_equal( '5 seconds', 5.to_time_units )
  end
  def test_minutes
   assert_equal( 'minute',     46.to_time_units )
   assert_equal( '10 minutes', (60*10.4).to_time_units )
  end
  def test_hours
   assert_equal( 'hour',    (60*60*1.2).to_time_units )
   assert_equal( '2 hours', (60*60*1.8).to_time_units )
  end
  def test_days
   assert_equal( 'day',     (60*60*24*0.95).to_time_units )
   assert_equal( '20 days', (60*60*24*20).to_time_units )
  end
  def test_months
   assert_equal( 'month',     (60*60*24*30*1.1).to_time_units )
   assert_equal( '10 months', (60*60*24*30*10).to_time_units )
  end
  def test_years
   assert_equal( 'year',     (60*60*24*30*14).to_time_units )
   assert_equal( '11 years', (60*60*24*365*11).to_time_units )
  end
end

[Numeric extension was here]