Why is my Perl script not using my module?

Question

module.pm

package module; use 5.012; use warnings; sub Parse { return 1; } 1; 

script.pl

 #!/usr/bin/perl -w use 5.012; use warnings; use lib 'C:/'; use module; print Parse("value"); 

Stdout

 Undefined subroutine &main::Parse 

Answer 1

You need to either write:

 print module::Parse("value"); 

or change the module package to export the name Parse .

See http://perldoc.perl.org/perlmod.html#Perl-Modules for a guide on exporting characters from your module.

(By the way, you really should call your module module , not module . The lower names of the modules are used for Perl built-in functions such as use warnings and use strict .)

Answer 2

Few things:

• First use Local as your module prefix. Thus, if you just have a module with the same name in your Perl installation, it will use yours. Name it "Local :: Module". Then create the Local directory and name your module Module.pm .

• Another thing you need to understand is that you define your module in a different namespace. By default, everything is in the main namespace until you use the package statement. This creates another namespace that your package uses. That way, if your package has a foo function, and you defined the foo function in your main program, they will not collide.

Thus, you have two options: one (preferably now) is to simply call your routine with the full package name added to it. The second way is to export the subroutine names into your main program. This can cause problems with duplicate names, but you do not need to constantly enter a package name every time you call your routine.

No name export

Local / Module.pm

 # /usr/bin/env perl # Local/Module.pm package Local::Module; use strict; use warnings; sub Parse { my $value = shift; #Might as well get it. print "I got a value of $value\n"; return $value; } 1; #Need this or the module won't load 

program.pl

 # /usr/bin/env perl # program.pl use strict; use warnings; use Local::Module; Local::Module::Parse("Foo"); 

---

When exporting:

Local / Module.pm

 # /usr/bin/env perl # Local/Module.pm package Local::Module; use strict; use warnings; use Exporter qw(import); our @EXPORT_OK(Parse); #Allows you to export this name into your main program sub Parse { my $value = shift; #Might as well get it. print "I got a value of $value\n"; return $value; } 1; #Need this or the module won't load 

program.pl

 # /usr/bin/env perl # program.pl use strict; use warnings; use Local::Module qw(Parse); Parse("Foo");