From: Peter Hickman <peter@...>
Date: 2008-02-15T22:48:52+09:00
Subject: Re: closing files with abrupt interruptions

Daniel Brumbaugh Keeney wrote:
> loop do
>   File.open somefile, 'r' do |io|
>     next
>   end
> end
>
> Does somefile get closed?
> How would I test that?
> I have the same question if it raises an error (that gets rescued) or
> throws a symbol.
>
> Daniel Brumbaugh Keeney
>
>
>   

There are two ways to open a file for reading in ruby, the first is:

f = File.open("fred.txt", "r")
  f.each do |l|
    puts l
  end
f.close

in the above case you have to explicitly close the file, however with this:

File.open("fred.txt","r")  do |f|
  f.each do |l|
    puts l
  end
end

The opened file is referenced by the variable f, however f is in the 
scope of the 'File.open() do ... end' and once the program goes past the 
closing 'end' the f will be removed. The deletion of the file handle 
triggers the close. So no need for an explicit close.

The second way is also more 'rubyish'.