From: Jos Backus <jos@...>
Date: 2004-12-05T04:50:57+09:00
Subject: Obtaining mode information on a File object

Another question... How do I access the File open mode ("w" in this case) on a
File object?  Example:

class Foo
  def initialize(file)
    begin
      yield self
    ensure
      # We only want to call finalize when the file was opened for writing;
      # The following doesn't work, but how _do_ you do this?
      finalize(file) if file.mode.writable? # file was opened with mode "w"
    end
  end
  def finalize(file)
    file.puts "END"
  end
end

File.open("foo", "w") do |file|
  a = Foo.new(file) do
    # ... Use a ...
  end
end

-- 
Jos Backus                       _/  _/_/_/      Sunnyvale, CA
                                _/  _/   _/
                               _/  _/_/_/
                          _/  _/  _/    _/
jos at catnook.com        _/_/   _/_/_/          require 'std/disclaimer'