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> -----Original Message-----
> From: sketchitup / gmail.com [mailto:sketchitup / gmail.com] 
> Sent: Wednesday, July 25, 2007 9:45 AM
> To: ruby-talk ML
> Subject: Detecting the end of a text file...
> 
> I'm just beginning to learn the Ruby progamming language, 
> although I have some previous programming experience in Java. 
> I would like to know if how I can detect the end of a file 
> when parsing a text file in Ruby. I don't want to throw an 
> error or exception when I reach the end of the file, I just 
> want to tell my parser to stop parsing.
> 
> Thanks for the help.
> 
> The SketchUp Artist
> 
> 

File.open("filename") do |file|
  while line  ile.gets
    puts line
  end
End

File.open in a block form such as above automatically closes the file neatly
at the end of the block.
The while loop inside the block assigns the next line from the file to the
variable "line". 
When there is no next line to read because the end of file has been reached,
the variable will be set to nil. Since the variable, apart from being
assigned, is also evaluated as part of the condition of the while loop, and
since nil evaluates to false, no more lines will be read once EOF has been
reached.

HTH,

Felix

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