From: Erik Veenstra <erikveen@...>
Date: 2007-06-29T21:52:21+09:00
Subject: Re: Feature Request: Special file '-' denoting stdin/stdout

It should be mentioned that both File.new and File.open are
able to receive file descriptors:

 $ ruby -e 'File.new(1).write 17' | ruby -e 'p File.new(0).read'
 "17"

 $ ruby -e 'File.open(1){|f| f.write 17}' | ruby -e 'p File.open(0){|
f| f.read}'
 "17"

 $ ruby -e 'f=File.new("test", "w") ; File.open(f.fileno){|f| f.write
17}'

 $ ruby -e 'f=File.new("test") ; p File.open(f.fileno){|f| f.read}'
 "17"

(note: 0==$stdin, 1==$stdout and 2==@stderr)

If you insist on using "-", you might want to have a look on
either of the implementations below.

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

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

 class YourFile < File
   def self.new(file, mode="r", *perm)
     if file == "-"
       mode.include?("r") ? $stdin : $stdout
     else
       super(file, mode, *perm)
     end
   end

   def self.open(file, mode="r", &block)
     if file == "-"
       super(new(file, mode).fileno, mode, &block)
     else
       super(file, mode, &block)
     end
   end
 end

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

 class File
   @@_non_dashed_new     = method(:new)
   @@_non_dashed_open    = method(:open)

   def self.new(file, mode="r", *perm)
     if file == "-"
       mode.include?("r") ? $stdin : $stdout
     else
       @@_non_dashed_new.call(file, mode, *perm)
     end
   end

   def self.open(file, mode="r", &block)
     if file == "-"
       @@_non_dashed_open.call(new(file, mode).fileno, mode, &block)
     else
       @@_non_dashed_open.call(file, mode, &block)
     end
   end
 end

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