From: Dan Schmidt <dfan@...>
Date: 2000-12-20T07:40:04+09:00
Subject: [ruby-talk:7717] Re: Code sample for improvement

Stephen White <steve@deaf.org> writes:

| During an idle chat with someone on IRC, they presented some fairly
| nasty code for printing a time interval in English. I cleaned it up
| a bit and converted it to Ruby.
| 
|   #! /usr/bin/env ruby
| 
|   # Given the number of seconds, convert to English description
| 
|   def format(size, singular, plural)
|     if size > 0
|       (size == 1) ? "#{size} #{singular} " : "#{size} #{plural} "
|     else
|       ""
|     end
|   end
| 
|   time = ARGV[0].to_i
| 
|   secs   = time % 60; time = time / 60
|   mins   = time % 60; time = time / 60
|   hours  = time % 24; time = time / 24
|   days   = time % 30; time = time / 30
|   months = time % 12; time = time / 12
|   years  = time
| 
|   res = ""
|   res += format(years,  'year',  'years')
|   res += format(months, 'month', 'months')
|   res += format(days,   'day',   'days')
|   res += format(hours,  'hour',  'hours')
|   res += format(mins,   'min',   'mins')
|   res += format(secs,   'sec',   'secs')
| 
|   puts res
| 
| Example run:
| 
|   [steve@localhost steve]$ ./a 10000
|   2 hours 46 mins 40 secs 
| 
| I was interested in how the new constructs available in Ruby, like
| closures and co-routines, could help clean up what really is pretty
| ghastly code.

I don't think closures and coroutines are going to be all that helpful
here.  Here's a translation that shows some of the power of Ruby,
though it's optimized mostly for cuteness:

def format (hash, name)
  size = hash[name]
  if size > 0
    "#{size} #{name}" + (size > 1 ? "s" : "")
  end
end

time = ARGV[0].to_i

Unit = Struct.new ("Unit", :name, :div)

units = [['year',  10000],
         ['month', 12],
         ['day',   30],
         ['hour',  24],
         ['min',   60],
         ['sec',   60]].map { |u| Unit.new (*u) }

t = {}
units.reverse.each { |u| (time, t[u.name]) = time.divmod(u.div)}
res = units.map { |u| format (t, u.name) } .join (' ').squeeze(' ').strip

puts res

-- 
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