From: "Florian Aßmann" <florian.assmann@...>
Date: 2007-06-15T06:53:33+09:00
Subject: Re: severe newbie question (class, fixnum, array)

Hi Colin,

First of all: http://whytheluckystiff.net/ruby/pickaxe/

Am 14.06.2007 um 23:25 schrieb Colin Summers:

> I worked a lot in tcl, and this is my first day of trying something in
> Ruby. Second, maybe.
>
> class Thread
>  def initialize number
>    @number = number ; #
>    @replies = 0 ;
>  end ; # initialize
>
>  def filename
>    dirname = "./data/" ; # the directory where the files are kept
>    filename = dirname + @number.toS + "-" + @replies.toS + ".html"
>    return filename
>  end ; # filename
>
> end ; # Thread definition
>
> puts "Finished definitions."
>
> thread[1727] = Thread.new 1727
>
> puts "The filename would be: "
> puts thread[1727].filename
>
>
> Of course, that doesn't work. It is unhappy with the code to create
> the filename, since .toS is not a method for fixnum (which apparently
> is what @number is, but I never TOLD it that was a fixnum).
See: http://whytheluckystiff.net/ruby/pickaxe/html/tut_stdtypes.html
The method you probably search for is to_s...

>
> And I can't seem to define "thread" to be an array of class Thread
> objects. I want to refer to thread[1702] and thread[291] and hop
> around like that.
class Thread already exists and is, as its name foreshadows, for  
http://whytheluckystiff.net/ruby/pickaxe/html/tut_threads.html

>
> (And, perhaps a more advanced question, right now I am making the
> thread number part of the object, ultimately for a gorgeous bit of
> code it seems like the object should just know the index of the array
> instead, so if I ask thread[32] what it's filename is it would know
> that it is thread #32. Can it do that?)
class FileThread
   DIR = 'data'.freeze # defines class constant
   @@instances = Array.new # initializes class variable as array

   def self.new number # overwrites class method
     @@instances[number] ||= super # set array elem with result from  
parent class if not already set
   end
   def self.[] number # defines new class method
     new number # class class method new
   end

   def initialize number
     @number = number
     @replies = 0
   end
   def filename
     # see http://whytheluckystiff.net/ruby/pickaxe/html/ref_c_file.html
     @filename ||= File.expand_path File.join( DIR, "#{ @number }-# 
{ @replies }.html" )
   end
end

FileThread[1].filename # => "#{ Dir.getwd }/data/1-0.html"

Sincerely
Florian