"Don't re-invent the wheel". Such is the underlying philosophy of programming - if you re-write a piece of code that's already been written and tested, you're probably wasting time that could also be better used. You're also likely to be creating a longer term support issue - someone's going to have to look after your code in the future.

Am I discouraging you from writing new code? Yes, if the code already exists. But no - there are still things to invent.

Having invented something, you should make it as easy as possible for others to find and use it:
* You should be writing your Perl code for distribution in classes /modules. That way, you can encapsulate the logic that you need within the class and provide a neat and short way for users and other programmers to make use of what you've written.
* You should be using the structure that's already been defined (and become something of a standard) to add your documentation, test routines and support files to your class; this will package it in a similar way to that in which it would be uploaded to the CPAN
* You should publicise your module well so that it can be found easily by anyone who searches for it, even if they don't know exactly what they're searching for.

Samples of files that make up a standard module are available on our web site and our Perl for Larger Projects course will be updated to include extra coverage on this topic before the next public run in December.

I'm giving a Perl course tomorrow, which is why I'm thinking Perl today - but the philosophy described here applies to PHP and the PEAR, Python and the Vaults of Parnassus [[ or now - the Cheeseshop ]] and elsewhere too.
(written 2004-11-08, updated 2006-06-05)

 P219 - Perl - Libraries and Resources
  [3377] What do I mean when I add things in Perl? - (2011-08-02)
  [3101] The week before Christmas - (2010-12-23)
  [3009] Expect in Perl - a short explanation and a practical example - (2010-10-22)
  [2931] Syncronise - software, trains, and buses. Please! - (2010-08-22)
  [2427] Operator overloading - redefining addition and other Perl tricks - (2009-09-27)
  [2234] Loading external code into Perl from a nonstandard directory - (2009-06-12)
  [2229] Do not re-invent the wheel - use a Perl module - (2009-06-11)
  [1865] Debugging and Data::Dumper in Perl - (2008-11-02)
  [1863] About dieing and exiting in Perl - (2008-11-01)
  [1444] Using English can slow you right down! - (2007-11-25)
  [1391] Ordnance Survey Grid Reference to Latitude / Longitude - (2007-10-14)
  [1235] Outputting numbers as words - MySQL with Perl or PHP - (2007-06-17)
  [1219] Judging the quality of contributed Perl code - (2007-06-06)
  [760] Self help in Perl - (2006-06-14)
  [737] Coloured text in a terminal from Perl - (2006-05-29)
  [712] Why reinvent the wheel - (2006-05-06)
  [358] Use standard Perl modules - (2005-06-25)
  [357] Where do Perl modules load from - (2005-06-24)
  [86] Talk review - Idiomatic Perl, David Cross - (2004-10-12)

Back to Training notes available under Open Distribution license

Previous and next or Horse's mouth home

Forward to A Parallel for Perl 6

The next generation of programmer
Expiration dates or times on web pages
Relative or absolute milkman
A Parallel for Perl 6
Avoid the wheel being re-invented by using Perl modules
Training notes available under Open Distribution license
Friday, busy week!
URLs - a service and not a hurdle
A typical morning
Taking Equipment offshore to run a course