Mac Forum / Programming / Perl / May 2007

The Camel book is a bit scary describing performance of filename globbing with the <*.pl> or the glob("*.pl") syntax with or without "use Cwd" in the preamble. Portability is declared questionable.

I find that the only thing that works is <*> within a loop where each file is tested by hand.

Consider this bit of doggerel.  I'm looking for special cases of a *.pl file that appears where * means the short name of the enclosing directory. Note especially the "last" command in the second while loop. It works not!  What happens is that the second pass through the while() loop begins in the previous directory at the point where it was cut short after finding the file I want. If I comment out the last statement, so that all of the files in the directory are processed, everything works.

my ($trial, $ddd, $lookfor, $error, $nextdir);
@thefolders = ();
@directories = ();
while ($trial = <*>)
   {
   if (-d $trial)
       {
       push @thefolders, $trial;
#      print REPORT "$trial\n";
       }
   }
for $ddd (@thefolders)
   {
   $lookfor = "$ddd.pl";
   $nextdir = "$mybase/$ddd";  # $mybase, global, is full path to initial directory.
   $error = chdir "$nextdir";
   while (<*>)
       {
       if ($_ eq $lookfor)
           {
           push @directories, $ddd;
#          print REPORT "Added directory $ddd,  $lookfor in $ddd\n";
#          last;  # Fails.  while() continues where it left off in the previous pass
           }
       }
   }

If I try finding <*.pl>, <$lookfor>, or glob("$lookfor") I get a real mess with hits from directories that bear no resemblance to the most recent chdir which returned without error.

Making the second while loop operate within the while looking for directories is even worse.

I'll probably get around to looking more deeply but there's little point if someone here knows that it's all a known problem on MacOS neXt.  (10.3.9 here because I need to talk to my SE/30 file server.) Oh It's perl 5.8.1-RC3.