Re: getting a while loop to terminate

[thezip]

in reply to getting a while loop to terminate

It's because you have set $flag to '0', which is an uninterpolated string containing the character '0', a true value.

Instead, you should set $flag to zero, (0), without the single quotes. This will evaluate to false and make your logic all happy.

[Anonymous Monk]

Nope :) See What is true and false in Perl?, Tutorial::What is true and false?, True or False? A Quick Reference Guide

$ perl -le " die 666 if q/0/ "

$ perl -le " die 666 if $what = q/0/ "

$ perl -le " die 666 if $what = q/1/ "
666 at -e line 1.

$ perl -le " die 666 if $what = q/0E0/ "
666 at -e line 1.

$ perl -le " die 666 if $what = q/0 but true/ "
666 at -e line 1.

[Datz_cozee75]

I guess I don't follow you here:

$  perl -le " die 666 if q/0/ "
$ perl -le " die 666 if $what = q/0/ "
syntax error at -e line 1, near "if  ="
Execution of -e aborted due to compilation errors.
$ 

[Anonymous Monk]

My shell doesn't interpolate $what, as you can see from the session I posted, use single quotes if your shell interpolates doubles

Or you could even omit  $what =

Whether it is assigned to a variable or not , '0' is always false

[Datz_cozee75]

Yay! first taste of victory....

$ perl tg1.pl
site_13 
$ cd site_13
$ ls
image_1   image_2   image_3  ...
$ cd ..
$ cat tg1.pl
#!/usr/bin/perl -w
use strict;
use WWW::Mechanize;
use LWP::Simple;

my $domain = 'http://www.yahoo.com';
my $m = WWW::Mechanize->new;
$m->get( $domain);
my $counter = 0;
my $dir = &dirname;
my @list = $m->images();
for my $img (@list) {
  my $url = $img->url_abs();
  $counter++;
  my $filename = "$dir". "/image_". "$counter";
  getstore($url,$filename) or die "Can't download '$url': $@\n";
  }
sub dirname {
  my $word = "site";
  my $counter = 1;
  my $flag = 1;
  while ($flag) {
    my $name = "$word" . "_" . "$counter";
    if ( -d $name) {
      $counter++;
      next;
      }
      else {
        mkdir $name, 0755 or warn "Cannot make dir $name:  $!";
        $flag = 0;
        }
  print "$name \n";
  return $name;
  }
}
$ 

I have a whole bunch of questions at this point, but don't want to ask them all. Let me ask this one, because it goes to readability: Is there an indent command that works well for perl? indent -i2 foo.pl was not a winner.

[GrandFather]

You may be looking for Perl::Tidy which does an excellent job of pretty printing Perl and is highly configurable.