[Omaha.pm] Fwd: Perl and recursion...

[Richard Norton]

I'd agree with Theodore's comments...without refering back to  
documentation, I'm pretty sure you're hitting a scoping issue on your DIR  
file handle.

As an alternative to frontloading all the filenames into an array, have  
you looked at the File::Find module?  It confused the heck out of me when  
I first looked at it, but once you figure it out, it can do all sorts of  
neat stuff with directory trees and their content.

Richard

On Tue, 15 Nov 2005 16:20:40 -0600, Theodore Katseres <tedkat at gmail.com>  
wrote:

> ---------- Forwarded message ----------
> From: Theodore Katseres <tedkat at gmail.com>
> Date: Nov 15, 2005 2:54 PM
> Subject: Re: [Omaha.pm] Perl and recursion...
> To: dan at linder.org
>
>
> Sorry, Your code was right!
> The problem seems to be with while test. It keeps DIR descriptor open
> thru the recursion. I think this is why it dives and then quits.
>
> By loading up your files and directories into memory before recursion
> you no longer depend on the File descriptor to keep its previous
> state.
>
>     opendir( DIR, $dir ) or die $!;
>     my @arr = grep { !/^\.+$/ } readdir(DIR); ## just ignore . and ..
>     close(DIR);
>
>     while .....
>
> On 11/15/05, Daniel Linder <dan at linder.org> wrote:
>> -----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1
>>  On Tue, November 15, 2005 13:31, Theodore Katseres wrote:
>>  > It appears that no recursion is happening passed the initial dive. {
>>  > ProcFiles("/tmp") }
>>
>>  I agree -- when I take out the '&ProcFiles("$dir/$file");' line, it
>> continues through the /tmp directory fine.  With the recursive call to
>> itself, I can watch the script dive into the sub-directory (/tmp/dir1),  
>> and
>> it processes all the files in /tmp/dir1, but when it finishes with the  
>> files
>> in "dir1" the program quits.  Unless I am missing something, I thought  
>> it
>> should go back one level to the initial invocation of ProcFiles and  
>> continue
>> where it left off there...
>>
>>  > Check my comments.
>>  >
>>  > <Snip && Replace>
>>  > #!/bin/perl -w
>>  > use strict;
>>  >
>>  > sub ProcFiles {
>>  > my $dir = shift;
>>  >
>>  > opendir( DIR, $dir ) or die $!;
>>  >
>>  > while ( my $file = readdir(DIR) ) {
>>  >
>>  > next if ( -d "$dir/$file" && $file =~ /^\./ );
>>  >
>>  > # above makes sure this block of code never gets executed
>>
>>  The line you mention ("next if ...") is used to make sure I skip the  
>> "."
>> and ".." entries in the subdirectory -- otherwise it would back out of  
>> the
>> "/tmp" to "/" and work there! :(  (It also has the effect of ignoring  
>> files
>> with a leading "." -- that's also by design.)
>>
>>  > if ( -d "$dir/$file" ) {
>>  >
>>  > printf( "Diving into\"%s/%s\".\n", $dir, $file );
>>  >
>>  > &ProcFiles("$dir/$file");
>>  >
>>  > next;
>>  >
>>  > }
>>  >
>>  > # your printing files that don't begin with "."
>>
>>  True -- in my real script, this print line is replaced with a small  
>> bit of
>> code to do some real work! In the example I posted to OLUG I wanted to  
>> keep
>> it simple and see if I could make it work...
>>
>>  > printf( "Adding\"%s/%s\".\n", $dir, $file );
>>  >
>>  > }
>>  >
>>  > closedir(DIR);
>>  >
>>  > }
>>  >
>>  > &ProcFiles("/tmp");
>>
>>  Ted, thanks for your input.
>>
>>  Dan
>>
>>  - - - - -
>>  "Wait for that wisest of all counselors, time." -- Pericles
>>  "I do not fear computer, I fear the lack of them." -- Isaac Asimov
>>  GPG fingerprint:6FFD DB94 7B96 0FD8 EADF 2EE0 B2B0 CC47 4FDE 9B68
>> -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.1 (GNU/Linux)
>> iD8DBQFDejqusrDMR0/em2gRAtT2AJ9cL6zR+u/XpmGtjXNCCM/Y9WDcvwCfY1Fp
>> qXscyNVDA6vb5H8MuKUrEtM= =mFaZ -----END PGP SIGNATURE-----
>
>
> --
> Ted Katseres
>       ||=O=||
>
>
> --
> Ted Katseres
>       ||=O=||
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