- NAMING GOALS
- NAMES TO AVOID
- Top-level namespaces
- All-lowercase name
- Avoid Simple, Easy, Reduced, Tiny, Fast, Small, Super, Hyper
- Avoid the too-general nouns like Devel, Sys, Text, Data
- Unicode and unicore are off-limits
Choose a good module name.
First and foremost: you are naming your module so that people can find
your module. It's as easy--and as difficult--as that.
Naming your Perl packages well is one of the most important things you
can do. Choose a good name and people will naturally find it on CPAN.
Choose a bad name, and your otherwise excellent code might never get a
download. Imagine your module going out to CPAN one day. Will people
look at your module name and instantly know what your module does?
Will its name fit in with everything else that's already on CPAN.
There isn't a set of formal rules, or even its less restrictive little
brother, guidelines, for naming your packages. Your module can use any
name that it likes, but like all names, a good one goes a long way.
email@example.com (the mailing list for PAUSE admins) and
firstname.lastname@example.org can help you choose a good name. Not only
are they generally good at names, but they also know quite a bit about
what is already on CPAN. They can help you choose a name that puts
your module into the right place with all of the other modules.
A module name must accomplish quite a bit in a few characters, and,
once chosen, you rarely have the opportunity to change it after people
start using it. The name of the module isn't for you; you don't need a
name because you created it and understand it. The name is for other
people, and those other people don't have any of the context that you
do. Your name needs to convey three things.
CPAN is mostly without context other than "This is something in Perl".
We can categorize modules, but that categorization lives outside the
module and disappears once someone downloads it, blogs about it, or
uses it in their code. As a maintenance programmer, what would you
think about seeing:
You might think that's a silly example, but we've seen modules without
a single vowel and no recognizable initializations.
The task or the feature the module provides has a context, usually
given to it by its author who created it to scratch some itch. In the
author's mind, it's always obvious what the module does and what the
name means. Other people don't have that context, and the name needs
to provide it.
For example, in the Debian Linux distribution, the package manager is
dpkg. As a name alone, however, that has no meaning to someone
who doesn't use Debian. In the context of Debian, it makes perfect
sense. In the context of Perl, it means nothing so people need extra
Almost any abbreviation or acronym is going to be ambiguous. If the
page of Google hits for your initialization isn't about your topic, then
you have the wrong name.
Describing key features
Some modules are designed for a particular task. Other modules perform
a general set of tasks. Your name should describe the level of
generality. What does an
HTML module do? Well, you really can't
tell from that name. How about
HTML::SimpleLinkExtor? Those names give you more information
about what the module can do for you. When you choose your name, when
want to show that same kindness to other people.
Many of the modules on CPAN work towards similar goals in different
ways, or work in the same way towards different goals. How many
Getopt modules can you find on CPAN? Can you tell
what they all do just from the name? If your module is going to live
under the same namespace as other modules, how is yours different? Why
should people use your module over modules with very similar names?
You can distribute applications as Perl distributions. Typically,
those sorts of distributions go under the
App namespace, like
App::Prove. The namespace implies
that its a ready-to-use program rather than a module.
By convention, the top-level
Local namespace should never conflict
with anything on CPAN. This allows you to be confident that the name
you choose under
Local isn't going to conflict with anything from
the outside world.
Some projects, such as Moose, DBI, DateTime, and Catalyst, try to
organize the activity under their namespace to ensure everything works
together nicely. If you want to add a module to such a project,
discuss it on their mailing list.
Co-operate. If your module would work as a patch to an existing
module, contact the author of that module and suggest this
possibility. Be polite. Document your changes carefully and supply
good tests. Also, this way you can get someone else maintaining your
NAMES TO AVOID
CPAN has been around since 1995, and over time the various
administrators have discovered or followed certain conventions to make
the designed anarchy a bit less chaotic. As an evolutionary process,
it is historically inconsistent but modernly optimal. That is, looking
at the past as an example might not be the best thing. Just because
other people did it doesn't mean you should.
In general, top level namespaces are bad, unless they are a nexus for
several modules under that namespace or they are a fanciful name that
describes something more application oriented. You might think that
DB is a good name because it's that database portion of your code,
but it doesn't say much about what it is doing, and it also happens
to be the namespace for the Perl debugger.
That doesn't mean that all top-level namespaces are bad. For
DBI provide a
functionality around an idea rather than a particular low-level or
general task. They don't live in a hierarchy because they are large
enough to stand on their own.
Even though the module naming is in practice a first-come first-served
process, it is quite impolite to grab top-level names. Yes, even if
your project/product is named with just a single word, please think of
people trying to find something that would help them in their
problems. Unless they know of your project/product, they might not
ever find your module.
Remember that though you may be the first to contribute to a
namespace, you may well not be the last or the only one. Someone
might later want to use the namespace, for something unrelated to your
Perl reserves all lowercase namespaces for pragmas. That doesn't mean
you can't write a pragma, but you should get the blessing of p5p
Net namespace is one of the most abused namespaces out there.
Originally designed as a home for the code that knows how to talk
various defined network protocols, such as FTP, HTTP, NNTP, and so on,
people started using it for code that merely used the network without
knowing anything about it. Modules that interact with websites use the
network, but they aren't about the network, and they have much better
WebService. If you are implementing a network
protocol rather than an application protocol, then
Net might be for
you. Otherwise, it isn't.
Avoid Simple, Easy, Reduced, Tiny, Fast, Small, Super, Hyper
Tiny are some of the
worst parts of the names on CPAN. They all indicate that the module is
a variation of another module, but why is that variation interesting?
It's usually missing or hiding some features, less flexible than the
original, and in most cases, tailored to the task the author needed.
What is that task though? Making it easy for you doesn't mean it's easy
for the next programmer.
Avoid the too-general nouns like Devel, Sys, Text, Data
Devel is mainly meant for modules to do with low-level debugging
of/inside Perl itself. It does not stand for "development" or
"developer" in general.
Sys is a complete disaster. Adding Sys:: in front of something is
completely redundant. We are sorry it ever got used. Yes, we know
there's Sys::Syslog in the core, and we are we ashamed because of it.
Text is most often very low in information, too. If your module is
working with a natural language or languages, use "Lingua::".
"Text::" is fine if your module is dealing with formatting of text,
for example. If you are thinking of using "Text" because your data is
"text", please don't.
Unicode and unicore are off-limits
Unicore/unicore is reserved for the use of the Perl core for Unicode
Avoid API, Interface, and the like
Your module is an API? No kidding? Don't waste space in your name
telling people what they already know. If your code wasn't an interface
of some sort, it wouldn't be very useful.
Naming the module after yourself
Many people, lacking other ideas about what their module does, just
use their own name. They might have really good names, but that
doesn't help anyone figure out what the code does, even if they do
Util to the end.
brian d foy