From: Robert Klemme <shortcutter@...>
Date: 2011-03-20T21:15:37+09:00
Subject: Re: A question about Ruby 1.9's "external encoding"

On 03/20/2011 01:38 AM, Albert Schlef wrote:
> I have the following program:
>
>    p Encoding.default_external
>    File.open('testing', 'w') do |f|
>      p f.external_encoding
>    end
>
> and when I run it I the following output:
>
>    #<Encoding:UTF-8>
>    nil
>
> In other words, the file's "external encoding" is nil. What does this
> mean? Shouldn't this be "UTF-8", the default external encoding?

--------------------------------------------------- IO#external_encoding
      io.external_encoding   => encoding

      From Ruby 1.9.1
------------------------------------------------------------------------
      Returns the Encoding object that represents the encoding of the
      file. If io is write mode and no encoding is specified, returns
      +nil+.

I'd say it means that the default encoding is used.

> BTW, "ruby1.9.1 -v" gives me:
>
>    ruby 1.9.1p378 (2010-01-10 revision 26273) [i486-linux]
>
> I'm using Ubuntu 10.04.1, and that's the most updated version of Ruby
> 1.9.1.
>

irb(main):001:0> Encoding.default_external
Encoding.default_external   Encoding.default_external=
irb(main):001:0> Encoding.default_external
=> #<Encoding:UTF-8>
irb(main):002:0> Encoding.default_internal
=> nil
irb(main):003:0> File.open("x","w"){|io| p io.external_encoding; io.puts 
"aä"}
nil
=> nil
irb(main):004:0> File.open("x","r:UTF-8"){|io| p io.external_encoding; 
io.read}
#<Encoding:UTF-8>
=> "aä\n"
irb(main):005:0>

Apparently the file *is* encoded in UTF-8 because I can read it without 
errors and get what I expect.

Kind regards

	robert