How do I group my package imports into a single custom package?

Question

Hi All..

Normally when I am writing the perl program . I used to include following package .

use strict ; 
use warnings ; 
use Data::Dumper ;

Now , I want like this, I will not include all this package for every program . for that
I will have these all package in my own package. like following.

my_packages.pm

package my_packages  ; 
{
use strict ;
use warnings ;
use Data::Dumper;
}
1;

So, that if I add my_packages.pm in perl program , it needs have all above packages .

Actually I have done this experimentation . But I am not able get this things . which means when I am using my_packages . I am not able get the functionality of "use strict, use warnings , use Data::Dumper ".

Someone help me out of this problem.....

Answer 1

See this:

package Foo;

use warnings;

sub import {
    warnings->import;
}

1;

And now:

$ perl <<CUT
> use Foo;
> \$a = 5; # backslash just to keep the $ from being eaten by shell
> CUT
Name "main::a" used only once: possible typo at - line 2.

Taken from Modern::Perl.

Answer 2

This is harder than you expect.

• For pragmas like strict and warnings you can pass them through.

• For modules that don't export functions such as object oriented ones, it will work.

• However for modules that export by default, like Data::Dumper (it gives you the Dumper() function in the package of the caller), it is trickier.

You can make it work by telling Exporter that there is an extra layer of magic:

So you could do:

package my_packages;

use strict;
use warnings;
use Data::Dumper; 
use IO::Socket;


$Exporter::ExportLevel = 1; # Tell Exporter to export to the caller

sub import {

    # Enable this in the callers package

    strict->import;       # pragma in caller
    warnings->import;     # pragma in caller
    Data::Dumper->import; # Adds Dumper() to caller

    # No need for IO::Socket since it's OO.

    return 1;
}

1;

For three modules, this hardly seems to be worth it.

Answer 3

Have a look at ToolSet, which does all the dirty import work for you.

Usage example from pod:

Creating a ToolSet:

# My/Tools.pm
package My::Tools;

use base 'ToolSet'; 

ToolSet->use_pragma( 'strict' );
ToolSet->use_pragma( 'warnings' );
ToolSet->use_pragma( qw/feature say switch/ ); # perl 5.10

# define exports from other modules
ToolSet->export(
 'Carp'          => undef,       # get the defaults
 'Scalar::Util'  => 'refaddr',   # or a specific list
);

# define exports from this module
our @EXPORT = qw( shout );
sub shout { print uc shift };

1; # modules must return true

Using a ToolSet:

use My::Tools;

# strict is on
# warnings are on
# Carp and refaddr are imported

carp "We can carp!";
print refaddr [];
shout "We can shout, too!";

/I3az/