http://qs1969.pair.com?node_id=11148620


in reply to Re: Modules 101 :: Using a Local Module from CPAN
in thread Modules 101 :: Using a Local Module from CPAN

Thanks choroba,

I'm afraid either solution doesn't work. When I change my script to:

use lib '/path/to/my/local/directory/';
use Script::Singleton;     # Line 6

[download]

...the output is still:

Can't locate Script/Singleton.pm in @INC (you may need to install the 
+Script::Singleton module) (@INC contains: /home/demo/pullWorkload/scp
+LRSIControllerDir/toys/ /etc/perl /usr/local/lib/x86_64-linux-gnu/per
+l/5.30.0 /usr/local/share/perl/5.30.0 /usr/lib/x86_64-linux-gnu/perl5
+/5.30 /usr/share/perl5 /usr/lib/x86_64-linux-gnu/perl/5.30 /usr/share
+/perl/5.30 /usr/local/lib/site_perl /usr/lib/x86_64-linux-gnu/perl-ba
+se) at ./testMe.perl line 6.

[download]

I note that the use lib must specify the directory, not the .PM file, BTW.

If the use lib doesn't add /path/to/my/local/directory/ to @INC, I'm at a loss on what might be the problem. Any thoughts...? Thank you for writing.

Replies are listed 'Best First'.
Re^3: Modules 101 :: Using a Local Module from CPAN
by hv (Prior) on Dec 06, 2022 at 18:46 UTC

    Perl always expects each :: in a module name to translate to a path separator in the directory hierarchy. So for the module Script::Singleton it will look for the file Singleton.pm in a subdirectory named Script underneath one of the directories specified in @INC.

    So if you want to reference it from /home/demo/pullWorkload/scpLRSIControllerDir/toys, you need to create /home/demo/pullWorkload/scpLRSIControllerDir/toys/Script (with mkdir), and put the file Singleton.pm in that directory.

    I would recommend this as a temporary solution only. For CPAN modules it is almost always preferable to keep them in a separate place - see other people's suggestions for how to do that.

    The handling of :: in module names is not trivial to find in the documentation. From perldoc -f use you will see that use Script::Singleton; is exactly equivalent to BEGIN { require Script::Singleton; Script::Singleton->import(); }. You then need to understand that since Script::Singleton is not in quotes, it is what perl calls a "bareword", and then find the part of perldoc -f require that describes this:

                If EXPR is a bareword, "require" assumes a .pm extension a
+nd
            replaces "::" with "/" in the filename for you, to make it
+ easy to
            load standard modules.

    [download]
[reply]
[d/l]
[select]
      Thanks hv! Yes! Yes, this is the piece of information I was hoping for. Thanks so much for writing, you've explained it well enough for me to understand it, which is a pretty big accomplishment, actually. Thank you, may the universe shower you in positive kudos today :)
[reply]

In Section Seekers of Perl Wisdom