From: "Aleksi Niemelä" <aleksi.niemela@...>
Date: 2000-12-20T05:20:47+09:00
Subject: [ruby-talk:7712] RE:  Code sample for improvement

> During an idle chat with someone on IRC

Welcome to #ruby-lang (at least on IRCNET). There's almost always someone
(Japan, Europe, States, and again).

> ..they presented some fairly nasty code for printing 
> a time interval in English

Here's my table driven shot. I tried to remove the logic for 's' suffixing,
but in the end there was more code to initialize the array. It might be a
little bit prettier to use real if instead of and-idiom.

> I was interested in how the new constructs available in Ruby

I'm sorry not to use any fancy constructs, but I simply don't see any use
for them in here.

Please forgive me if two of the lines are too long.

  #! /usr/bin/env ruby

  # Given the number of seconds, convert to English description

  def format(time)
    res = ""
    [ ["sec", 60], ["min",   60], ["hour", 24], 
      ["day", 30], ["month", 12], ["year",  1]].each do |name, unit|
      time > 0 and 
        res = " #{time%unit} #{name}#{time%unit == 1 ? '' : 's'}" + res
      time /= unit
    end
    res
  end

  time = ARGV[0].to_i

  puts format(time)

The problem with this solution is that always that something is printed
there will be a leading whitespace. To get rid of that we could forget the
string building and instead collect the parts and print them out. (Had I
chosen shorter names the if could be in modifier form instead of this
full-blown form.)

  def format(time)
    parts = []
    [ ["sec", 60], ["min",   60], ["hour", 24], 
      ["day", 30], ["month", 12], ["year",  1]].each do |name, unit|
      if time > 0
        parts <<  "#{time%unit} #{name}#{time%unit == 1 ? '' : 's'}" 
      end
      time /= unit
    end
    parts.reverse.join ' '
  end

To tell something how I ended up with this code I could say that the
beautiful way you presented your code lead me immediately to the table
driven solution:

  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')

There are two easily seen tables. First one with the divisioning and second
one with naming. Further it could be seen that all plural forms are the same
as singular plus 's'. After that it's just layouting.

In any case the interface should be like it is on my version. It's all up to
method format how to do the magic. It could be implemented on your way, or
mine.

As a commentary to original problem, I'd like to ask is it really meant that
the output with 0 is an empty string or was it just a simplification?

	- Aleksi