Another perl coding challenge

[Eugene Tsyrklevich]

~sdpm~
perldoc File::Find

use File::Find;
find({/\.wel$/ && -f $_ && -T _ && -r _ && print}, $DIR);

good enough? ;-)

cheers


On Thu, Dec 28, 2000 at 06:59:02PM -0800, Todd Rockhold wrote:
> ~sdpm~
> Probably not as fun as Garrett's "reversible NAND gate" problem, but here is
> one I have encountered. I have a test system (Perl 5.6) and a production
> system (Perl 5.005).  I would like to run the tree walker on the production
> system.
> 
> The following code walks  a directory tree if run with Perl 5.6 but fails
> with earlier versions.  How do I modify it so that it will work with Perl
> 5.005?
> 
> ----------------------------------------------------------------------------
> --------------------------------------------------------------
> 
> my $DIR = "//yogi/yogidata/OntoCHROMRun/TestRuns";  # contains well files
> my $it = make_treewalker($DIR, \&is_well_file, sub {@{$_[1]}});
> while (defined (my $f_it=$it->()))  
> {
>    # process the interesting file
>    print "found file: $f_it\n";
> }
> 
> sub make_treewalker    #black magic to walk the directory tree
>    {
>      my @queue = shift();
>      my ($is_interesting, $userparam) = @_;
>      return sub
>        {
>  	while(1)
>  	  {
>  	    return undef unless @queue;
>  	    my $cur = shift @queue;
>  	    if (-d $cur && opendir my $dh, $cur)
>  	      {
>  		my @files = grep {$_ ne '.' && $_ ne '..'} (readdir $dh);
> 		push @queue, map {"$cur/$_"} @files;
>  	      }
>  	    return $cur if $is_interesting->($cur, $userparam);
>  	  }
>        }
>    }
> 
> 
> sub is_well_file # what files do we care about?
>   {
>     return () unless -f $_[0] && -T $_[0];  # gotta be a simple file
>     return () unless open FH, "< $_[0]";    # gotta be able to open it
>     return ($_[0]) if $_[0] =~ /\.wel/i ;   # gotta be a .WEL file
>     return ();                              
>   }
~sdpm~

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