one key hash

Bob Forgey rforgey at
Thu Feb 24 17:16:12 CST 2000


I think the hash is fine. You're putting together a set (of the
top-level directories), and then counting the number of elements. In
perl, a set is implemented as a hash in which you only care about the
keys. I would probably use
instead of the `each %foo_h', just to be explicit. Also, I would
change the regexp

so when I look at it, instead of wondering which string of non-/ it
matches, it's clear that the first one is what's wanted.

I presume you're using `tar tvf ...', which is the reason for the map
function, instead of a chomp?


>>>>> "CA" == C Abney <cabney at> writes:

    CA> ~sdpm~
    CA> I'm wondering if anyone can come up with a nicer way to get this key.
    CA> Or even dump the hash altogether.  I'm using:

    CA> 	$top = each (%foo_h);

    CA> By nicer I guess I mean more direct.  I find this misleading.

    CA> It's a part of the same script, in which I'm checking the manifest of
    CA> a tarball for what are (to my mind) unexpected features.  Obviously I'm
    CA> automating an install (shhh!) of some software, and want to make sure
    CA> nothing tooo out of the ordinary is happening while I'm not looking.

    CA> It's a part of this code sequence:

    CA> 	...

    CA> 	@flist = map +(split)[-1], @tarout;

    CA> 	log_n_die ( "Unpack from rootdir, Huh?" ) if ( $flist[0] =~ /^\// );

    CA> 	# this grabs the topmost directory/file name(s) from the tar manifest
    CA> 	for (@flist) { $foo_h{$1}++ if /([^\/]+)/; };

    CA> 	log_n_die ( "No top-level directory!!!" ) if ( keys (%foo_h) != 1);

    CA> 	$top = each (%foo_h);

    CA> 	... # more checks, unpacking stuff

    CA> 	log_n_die ( "Couldn't find PBS source dir, $top" ) unless ( -d $top );

    CA> 	... # and so on...

    CA> I'd also appreciate a lecture on regular expressions...<g>  One of the
    CA> biggest gripes I hear about Perl is its obscure syntax and resulting
    CA> poor maintainability.  I KNOW that's wrong!  I don't want to contribute
    CA> to that perception and therefore welcome any hints (but I'm off topic
    CA> now, and it's my own post, so... )

    CA> Perhaps you've noticed this is very closely related to what I posted
    CA> last time!  I'm really not a slow coder, honest. Really. Weell, I have
    CA> a lot of other things that get in the way. Or something. Oh, this is
    CA> the next revision! Yeah, that's it.

    CA> Anyway, anyone have a better way to do this?

    CA> p.s. Sorry I missed the meeting.  How'd it go?

    CA> CA
    CA> -- 
    CA> Mighty Mouse is a cartoon. Superman is a real guy. No way a cartoon
    CA> could beat up a real guy! -- Teddy                         C. Abney

    CA> ~sdpm~


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