What's the right way to import a module

sriharsha.sm has asked for the wisdom of the Perl Monks concerning the following question:

Is there any difference between the following two codes which is used to import the modules? If so which is the recommended practice?

use Foo;
use Foo::Bar;
[download]

and

use Foo::Bar;
[download]

Comment on What's the right way to import a module Select or Download Code

Replies are listed 'Best First'.
Re: What's the right way to import a module by moritz (Cardinal) on Apr 26, 2012 at 07:33 UTC
`Foo` and `Foo::Bar` are not related a priori. So the difference is that one uses `Foo`, and the other does not. The best practice is to use Foo if you need Foo, otherwise not. Perl 6 - the future is here, just unevenly distributed	[reply] [d/l] [select]
Re: What's the right way to import a module by Anonymous Monk on Apr 26, 2012 at 07:14 UTC
The two are not equivalent. See Simple Module Tutorial, use, require, import	[reply]
Re: What's the right way to import a module by tobyink (Canon) on Apr 26, 2012 at 07:56 UTC
The difference is: The first one uses the `Foo` module. The second one does not use the `Foo` module. `perl -E'sub Monkey::do{say$_,for@_,do{($monkey=[caller(0)]->[3])=~s{::}{ }and$monkey}}"Monkey say"->Monkey::do'`	[reply] [d/l] [select]
Re^2: What's the right way to import a module by sriharsha.sm (Initiate) on Apr 26, 2012 at 08:13 UTC
Foo package has only two modules: Bar and Car. Directory structure `- Foo \|-Car.pm \|-Bar.pm` [download] I intend to use only Foo::Bar module, but one of my colleague said its "best practice" to include 'use Foo' and then include 'use Foo::Bar'. Is this the right way of importing?	[reply] [d/l]
Re^3: What's the right way to import a module by Corion (Patriarch) on Apr 26, 2012 at 08:20 UTC
No. If there is no `Foo.pm`, and you don't use any functionality of `Foo.pm` then `use Foo;` will not work and is not considered best practice. There is no general hierarchical relationship between `Foo` and `Foo::Bar` and `Foo::Car`. Maybe if you wrote the modules, there is some relationship between `Foo::Bar` and `Foo::Car`, but in general, this is not true.	[reply] [d/l] [select]
Re^3: What's the right way to import a module by JavaFan (Canon) on Apr 26, 2012 at 08:34 UTC
one of my colleague said its "best practice" to include 'use Foo' and then include 'use Foo::Bar' Either there's more to it than you're telling us (perhaps things are set up in your work environment that it does make sense), or it's time to replace your colleague with someone with a basic understanding of Perl.	[reply]

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