From: David Alan Black <dblack@...4355dfae.dyn.optonline.net>
Date: 2004-04-09T10:44:16+09:00
Subject: Re: need help with recursion

Hi --

Mark Hubbart <discord@mac.com> writes:

> On Apr 8, 2004, at 5:54 PM, Boris "BXS" Schulz wrote:
> 
> > Hi,
> >
> > I was just trying to replace the underscores I get when using files 
> > from my Linux-friends, but somehow my code seems to be corrupt.
> > The code runs fine without the recursion, so it must be something 
> > wrong in those three lines, but I do not know what :-(
> > The "under_score.txt" is my testobject.
> > I am using: Ruby 1.8.0, Windows XP
> > Any help would be great.
> >
> > greetings, BXS
> >
> >
> > This is my code:
> >
> > class FileHandling
> > 	def noRecursiveUnderscore(basedirectory)
> > 		Dir::foreach(basedirectory){ |filename|
> > 		if File.stat(filename).file?
> > 			newname = filename.gsub("_", " ")
> > 			File.rename(filename, newname)
> > 		end
> > 		if File.stat(filename).directory? and filename != "." and filename 
> > != ".."
> > 			noRecursiveUnderscore(filename)
> > 		end
> > 		}
> > 	end
> >
> > end #class
> >
> > testDir = FileHandling.new()
> > testDir.noRecursiveUnderscore(Dir.getwd)
> >
> >
> > **** This is my errormessage ****
> > recursivenounderscore.rb:4:in `stat': No such file or directory - 
> > under_score.txt
> >   (Errno::ENOENT)
> > [...]
> 
> You are correct, the problem *is* in the recursion part; you are 
> stat()ing the same filename "with_underscores", but you had already 
> renamed the file, so it gave an error. To fix it, make it an 
> if..elsif..end, rather than two if..end's:
> 
> 		if File.stat(filename).file?
> 			newname = filename.gsub("_", " ")
> 			File.rename(filename, newname)
> 		elsif File.stat(filename).directory? and filename != "." and filename 
> != ".."
> 			noRecursiveUnderscore(filename)
> 		end


You'll still have the subdirectory problem.  Let's say you've got:

   a
   a/b
   a/b/under_score.txt

It will run the method for b, and filename will be set to
under_score.txt.  But when it stats it, it will stat it with respect
to a, unless you do a chdir to b or expand the path.


David

-- 
David Alan Black
home: dblack@wobblini.net        # New email address
work: blackdav@shu.edu
Web:  http://pirate.shu.edu/~blackdav