From: Erik Veenstra <pan@...>
Date: 2006-01-01T06:57:55+09:00
Subject: Re: my stupid code ...

> I'm trying to write a small ruby script which accepts:
>
>  1. Input : File or $stdin
>  2. Output : File or $stdout

Abstraction is the keyword. Put the decision to open a file or
stdin or stdout in a a method on the class File and put that
code in a library. That keeps your application clean and
simple.

gegroet,
Erik V. - http://www.erikveen.dds.nl/

----------------------------------------------------------------

 # LIBRARY

 class File
   def self.open_std(file, mode="r", *rest, &block)
     if file.nil?
       if block_given?
         block.call(mode.include?("r") ?  $stdin : $stdout)
       else
         mode.include?("r") ? $stdin : $stdout
       end
     else
       File.open(file, mode, *rest, &block)
     end
   end
 end

----------------------------------------------------------------

 # APPLICATION

 require "your_library"

 def do_some_thing(str)
   # do some things over str
   str.upcase
 end

 File.open_std(ARGV.shift, "r") do |f_in|
   File.open_std(ARGV.shift, "w") do |f_out|
     f_in.each do |line|
       f_out.puts do_some_thing(line)
     end
   end
 end

----------------------------------------------------------------