Export function from module

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

Hello Monks, I am writing a module and would like to export its functions. Looking at some docs it seems relatively straight forward, but I always seems to get an error and cannot seem to figure out why. Undefined subroutine &main::foo called at h line 10.
Both the module and script are in the same directory.

Module = HELPER.pm

package Helper;

use strict;
use warnings;

use Exporter qw(import);
our @ISA =   qw(Exporter);
our @EXPORT = qw(foo);

sub foo {
    print "foo\n";
}

sub bar {
    print "bar\n";
}

1;
[download]

Calling Script test.pl

#!/usr/bin/perl

use strict;
use warnings;
use HELPER;


print "In Main\n";

foo();
[download]

It does work if I prefix foo with the package name Helper::foo, but I was hoping to avoid that.

any help would be appreciated -- thanks

Comment on Export function from module Select or Download Code

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Re: Export function from module by davido (Cardinal) on Apr 30, 2013 at 02:48 UTC
The first line of HELPER.pm says: `package Helper`. The 5th line of `test.pl` is `use HELPER;` Though your filesystem may or may not be case-sensitive, package names are identifiers, and Perl's identifiers are case sensitive. You should be consistent in your use of case. I recommend naming the module Helper.pm, the package, Helper, and then "use Helper;". But if you prefer all caps, make sure your package name is all caps too. Dave	[reply] [d/l] [select]
Re^2: Export function from module by Anonymous Monk on Apr 30, 2013 at 03:39 UTC
Thanks for the reply Dave... That did the trick, but now I am confused. I though the use HELPER, simply imports packages from a file. Then by my exporting the functions I wish to be available, I simply need to call the function and the functions exported in the package are available to the calling script. What part am I missing? thanks	[reply]
Re^3: Export function from module by davido (Cardinal) on Apr 30, 2013 at 04:43 UTC
`use HELPER;`: Perl looks for a file named HELPER.pm from among the paths listed in `@INC`, and it is found. But `use HELPER;` is the same as saying: `BEGIN{ require HELPER; HELPER->import(); }` [download] The problem is that second part; you have inherited Exporter into a package named `Helper`. So when Perl goes looking for HELPER->import() it doesn't find anything. And what does exist, `Helper->import()` isn't being called, because you're using HELPER, not Helper. You may as well be saying: `BEGIN { require HELPER; Goofy->import(); }` [download] Additonally, the fully qualified name of `foo()` isn't HELPER::foo, it's Helper::foo. Dave	[reply] [d/l] [select]
Re^3: Export function from module by 2teez (Vicar) on Apr 30, 2013 at 04:56 UTC
Hi AM, I want to believe the Anonymous Monk is the OP iang. If so, what other errors are you getting? Dave have pointed out that explicitly, that the package you used is Helper not HELPER. Hope, your module is also saved as Helper.pm not HELPER.pm. That been said, don't forget you only `"exported"` the `foo` subroutine. However, if you still wanted the `bar` subroutine, then use `Helper::bar()` in your script. UPDATE: Oouch!! Davido, got that answered before me !!! Why am i this slow typing..Ah... Nice one, faster fingers. If you tell me, I'll forget. If you show me, I'll remember. if you involve me, I'll understand. --- Author unknown to me	[reply] [d/l]