or with a block

GhodMode has asked for the wisdom of the Perl Monks concerning the following question:

I want to opendir, then if it fails, I want to execute a block of code, rather than just warn or die. It seems like this should work:

opendir(DIR, "$path")
   or {
      warn "Could not open directory, $path: $!\n";
      next;
   };
[download]

but I get a syntax error near warn and the closing bracket of the block. This works, but seems sloppy:

opendir (CLEANPATH, "$path")
   or my $openfailed = "TRUE";
   if ( defined $openfailed ) {
      warn "Could not open directory, $path : $!\n";
      next;
   }
[download]

What's the best way to do it?

Comment on or with a block Select or Download Code

Replies are listed 'Best First'.
Re: or with a block by dws (Chancellor) on May 31, 2002 at 18:35 UTC
I want to opendir, then if it fails, I want to execute a block of code, rather than just warn or die. It seems like this should work: The word you're looking for is "do". Try `opendir(CLEANPATH, $path) or do { ... };` This still leaves you with a flow-of-control issue. You still need a `closedir()` if the `opendir()` succeeds. (Yeah, you can neglect this in a short script, though coding as if each script could be long-running has benefits.) For this, I prefer to be a do `if ( opendir(CLEANPATH, $path) ) { ... closedir(CLEANPATH); } else { ... }` [download]	[reply] [d/l] [select]
Re: or with a block by Abigail-II (Bishop) on Jun 03, 2002 at 11:13 UTC
The use of `next` in the original code suggests that it's inside a loop. In that case, you can make Perl automatically deal with closing the directory. `for my $path (...) { # Or a while opendir my $dir => $path or do { warn ...; next; } ... something with $dir ... }` [download] Abigail	[reply] [d/l] [select]
Re: Re: or with a block by GhodMode (Pilgrim) on May 31, 2002 at 19:07 UTC
Perfect! I like your method. I tried the do first, but I got a "BAREWORD" error for the closedir argument when the directory could not be opened. (I'm using strict). Thanks, Vince	[reply]
Re: or with a block by maverick (Curate) on May 31, 2002 at 18:42 UTC
I tend to do it like this: `unless(opendir(CLEANPATH,"$path")) { warn "$path: $!\n"; next; }` [download] It reads kinda nicely. "unless we can open the directory, yell" Some people might dislike that technique since the evalaution of the conditional has a side effect (that the directory is opened)...but I think it'd like it better than the right hand side of an inlined 'or' having one... ;) /\/\averick OmG! They killed tilly! You bleep!!	[reply] [d/l]
Re: or with a block by kpo (Initiate) on Jun 01, 2002 at 06:55 UTC
just thought id point out another obvious solution... `opendir(DIR, "$path") or warn $!; yell(); sub yell() { #other code here... }` [download]	[reply] [d/l]