From: Jeremy Hinegardner <jeremy@...>
Date: 2006-10-27T15:22:58+09:00
Subject: Re: Time without Date

On Fri, Oct 27, 2006 at 12:50:03PM +0900, ara.t.howard@noaa.gov wrote:
> On Fri, 27 Oct 2006, _Kevin wrote:
> 
> >
> >List Recv wrote:
> >>Related question:
> >>
> >>Is there a way to convert a Time (or DateTime) to Ruby's Date class?
> >
> >I added a few conversion methods like this to 'ruby-units' gem
> >
> >class Time
> >def to_datetime
> >   DateTime.civil(1970,1,1)+(self.to_f+self.gmt_offset)/86400
> > end
> >
> > def to_date
> >   Date.civil(1970,1,1)+(self.to_f+self.gmt_offset)/86400
> > end
> >end
> >
> >This seems to work pretty well, although I haven't tested it on a wide
> >range of OSs.
> 
> it's nice to have
> 
>   Time.to_time
>   Time.to_date
> 
>   Date.to_time
>   Date.to_date
> 
>   DateTime.to_time
>   DateTime.to_date
> 
> so you can do
> 
>   do_not_care_which_one.to_time
>   do_not_care_which_one.to_date
> 
> a la rails.
> 
> 2 cts.

And that's why we have facets!

    % gem install facets
    % cat date-time.rb
    require 'date'
    require 'rubygems'
    require 'facets'
    require 'date/to_time'
    require 'date/to_date'
    require 'time/to_date'
    require 'time/to_time'

    timers = {
        :date => Date.today,
        :time => Time.now,
        :date_time => DateTime.now
    }

    ["to_date", "to_time"].each do |method|
        timers.each_pair do |name,time|
            result      = time.send(method)
            class_name  = result.class.name
            puts "#{name.to_s.rjust(10)}.#{method} yields result #{result} with class of #{class_name}"
        end
    end

    puts
    puts "superclass of DateTime : #{DateTime.superclass}"


    % ruby date-time.rb
          date.to_date yields result 2006-10-27 with class of Date
          time.to_date yields result 2006-10-27 with class of Date
     date_time.to_date yields result 2006-10-27T00:18:27-0600 with class of DateTime
          date.to_time yields result Fri Oct 27 00:00:00 -0600 2006 with class of Time
          time.to_time yields result Fri Oct 27 00:18:27 -0600 2006 with class of Time
     date_time.to_time yields result Fri Oct 27 00:00:00 -0600 2006 with class of Time

    superclass of DateTime : Date

When to_date is called on an instance of DateTime its still calling it
on Date object since DateTime.superclass == Date.  So anywhere a Date is
used, a DateTime can be used.

enjoy,

-jeremy

-- 
========================================================================
 Jeremy Hinegardner                              jeremy@hinegardner.org