Re^2: 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.

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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]
Re^4: Modules 101 :: Using a Local Module from CPAN by redapplesonly (Sexton) on Dec 06, 2022 at 19:41 UTC
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]


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