From: Mike Kasick <mkasick-rt@...>
Date: 2009-07-24T11:10:32+09:00
Subject: ARGF.eof? behavior

Hi folks,

In Ruby 1.8, I know that:

$ ruby -e 'while !ARGF.eof?; puts ARGF.readline; end' /tmp/foo /tmp/bar

prints every line in /tmp/foo, but not /tmp/bar.  However, in Ruby 1.9:

$ ruby1.9 -e 'p ARGF.eof?' /tmp/foo
true

Which means that lines from neither /tmp/foo nor /tmp/bar would be printed
in the first example.  Is this an expected change in behavior?  Seems to be
consistent for both 1.9.1p0 and the 1.9.2 svn trunk I just compiled.

If it is, it's not that big of a deal, except I'm not sure how to "switch
ARGF" to the next file without calling ARGF.gets or ARGF.readline.

For example, is there a method to complete the following code, so as to
print lines from all files listed in ARGV?

  while !ARGV.empty?
    # ARGF.some_method_to_advance_to_next_file

    while !ARGF.eof?
      puts ARGF.readline
    end
  end

I know I can use ARGF.each, gets, or readline.  However, I'm really calling
a parsing method that takes ARGF as an argument and calls readline on my
behalf.  I'd like to able to distinguish between EOFErrors due to reaching
EOF before parsing (no more data records), and EOFErrors due to reaching
EOF during parsing (an incomplete data record).

Thanks!