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

Hi Monks!
I'm right on a deadline and everything was working perfect. Then I made some comments, put use strict in all modules and one 'my' that was missing to compile with strict and when trying to compile, I got this:

Unknown error
Compilation failed in require at BookRetriever.pm line 8.
BEGIN failed--compilation aborted at BookRetriever.pm line 8.
Compilation failed in require at compare_prices.pl line 4.
BEGIN failed--compilation aborted at compare_prices.pl line 4.

These are the first lines of BookRetriever:

package BookRetriever;
####################################################
# This class uses Vendor plugins to retrieve book HTML pages from vend
+or websites,
# parse them, insert it into db and return data from db

use DBI;
use LWP::UserAgent;
use Vendor::Amazon; # LINE 8
use Vendor::BarnesNoble;

# Here is configuration for everything
our %CONFIG = ('db_host' => 'localhost',
           'db_name' => 'books',
           'db_user' => 'user',
           'db_pass' => 'pass',
           'html_retrieve_timeout' => 30,
           'vendors' => [ qw(Amazon BarnesNoble) ] 
        );

[download]
error line is this use Vendor::Amazon, and error happens Vendor::BarnesNobles if I exchange them. In fact, I made one change right there. It was working, them I erased these two lines, put a BEGIN around our %CONFIG and inside the BEGIN I looped through @{$CONFIG{'vendors'}} and eval "use Vendor::$vendor;";
I kept writing comments all around before testing then noticed the eval didn't work, when I got back the old way it didn't compile
Any ideas?

janitored by ybiC: Balanced <code> tags around codeblock, renamed from "Unknown compile error - desperation"

Replies are listed 'Best First'.
Re: Unknown compile error - desperation
by ysth (Canon) on Feb 23, 2004 at 03:44 UTC
    If I understand it correctly, "Unknown error" results when a require fails in a way that should have set $@ but didn't. You can often get to the actual error by feeding perl directly the .pm file (.../Vendor/Amazon.pm or BarnesNoble.pm, in this case). You should report this using perlbug.
[reply]
      I got, thanks for all! The problem was that Vendor::Amazon had: 
      use base Vendor::Base;

      [download]
      one thing I did but couldn't associate with was: 
      use strict;
use base Vendor::Base;

      [download]
      then I realized that if strict goes after, no problem. Later I figured all out: base is the module and Vendor::Base is the parameter, so quotes are necessary around Vendor::Base. with strict after or without strict, no problem without quote.

      That's it. Thanks again.

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[d/l]
[select]
Re: Unknown compile error - desperation
by AidanLee (Chaplain) on Feb 23, 2004 at 02:18 UTC
    i had an 'unknown error' earlier this week. I wrapped the offending code in an eval, and $@ pointed me to the real problem.
[reply]
Re: Unknown compile error - desperation
by NetWallah (Canon) on Feb 23, 2004 at 03:05 UTC
    Your line "'vendors' => qw(Amazon BarnesNoble) " is probably not doing what you expect.assigning a list to a scalar. This will result in the first value (Amazon) being assigned to "vendors".

    Update:Valid Nit from message below has been picked.

    What I think you meant is to get a REFERENCE to a list, which you can do thus: 

    our %CONFIG = ('db_host' => 'localhost',
'db_name' => 'books',
'db_user' => 'user',
'db_pass' => 'pass',
'html_retrieve_timeout' => 30,
'vendors' => [qw(Amazon BarnesNoble)]
);
# Dereference thus:
print  @{$CONFIG{vendors}};

    [download]
    "Experience is a wonderful thing. It enables you to recognize a mistake when you make it again."
[reply]
[d/l]
      I agree that the op probably wants an anonymous reference for the value of the %CONFIG{vendors}, but here's a nit.
      Your line "'vendors' => qw(Amazon BarnesNoble) " is assigning a list to a scalar. This will result in the first value (Amazon) being assigned to "vendors"

      Actually, it's assigning an odd number of elements to a hash: 'vendors', 'Amazon', 'BarnesNoble' are the last three.

[reply]
[d/l]
      This is a reference to a list 
      use Data::Dumper;
print Dumper( \( 1, 3, 4, 6, $_, %_ ) );
__END__
$VAR1 = \1;
$VAR2 = \3;
$VAR3 = \4;
$VAR4 = \6;
$VAR5 = \undef;
$VAR6 = {};

      [download]
      A list is not a data structure.
[reply]
[d/l]

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