Beefy Boxes and Bandwidth Generously Provided by pair Networks
Perl: the Markov chain saw

comment on

( #3333=superdoc: print w/replies, xml ) Need Help??
  • Do use CGI, or CGI::Simple.
  • Do use strict and warnings and CGI::Carp from the start.
  • Do use templates (HTML::Template or Template::Toolkit)
  • Do write yourself a requirements list if possible.
  • Do design the whole thing before you start
    • what administration pages will you need?
    • what sequence of events will customers follow?
  • Do create your test cases and scaffolding before you start.
  • Do make paper webpage mockups and walk through the client process with a non-geek, perhaps your father?
  • Do try to identify all the code you can dump into separate libraries
  • Do consider OO where it might be useful.
  • Do search CPAN, freshmeat and sourceforge to see if your system or parts of it have already been done before.
  • Do ask here to see if we know where it's been done before.
  • Do use CPAN modules to do the parts of your project that they can.
  • Do make sure that the modules you choose to use are well supported and suit the task you're using them for.
  • Do use taint checking. Lots. Always.
  • Do expect to throw parts away once you've found a better solution
  • Do throw away parts when you've found a better solution
  • Do use DBI and its friends if it's DB related
  • Do investigate the pros and cons of different databases before starting
  • Do read about useability and try to design your system to be useable by a large range of skill levels and disabilities.
  • Do think about open-sourcing the end result if you're happy with it.
  • Do comment it thoroughly
  • Do be consistent in your coding style - and please use one that is considered "standard" (K&R, GNU or another)
  • Do try to keep each subroutine less than two screenfuls (ie less than 50 lines) because even if you don't succeed it's a good metric.
  • Do try to refactor as much as possible, whenever possible so that your library code grows faster than your scripts do.
  • Do test and test and test again. And get someone else to test too.
  • Do use a decent change management system such as CVS. Use it properly and tag releases (where it compiles, works and is stable (though not necessarily complete)).
  • Do document your module/function interfaces and keep these documents up to date.


  • Don't expect it to be easy
  • Don't skim on requirements or design
  • Don't reinvent the wheel just for the hell of it
  • Don't refuse constructive criticism
  • Don't write ugly code and then beg us to fix it for you :)
  • Don't give up, large projects are a great way to improve at your chosen language.
  • Don't use global variables unless you absolutely need to, in fact, don't use them then either.
  • Don't hardcode in URLs, filenames, HTML headers, magic numbers. Try to move these to a good localisation module.
  • Don't turn strict off. If you need to turn it off, you're probably trying to do something a wrong way.
  • Don't keep code just because it took you ages to write it. When you've found a much more elegant/efficient/effective solution, fix your code.
  • Don't spend all your time worrying about finding the absolute best way to do something. Do it any way the first time and come back and rewrite at your leisure.

Update:A few more don'ts.

In reply to Re: Writing a large application in perl? by jarich
in thread Writing a large application in perl? by BUU

Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post; it's "PerlMonks-approved HTML":

  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.
  • Log In?

    What's my password?
    Create A New User
    and the web crawler heard nothing...

    How do I use this? | Other CB clients
    Other Users?
    Others perusing the Monastery: (7)
    As of 2021-03-02 17:40 GMT
    Find Nodes?
      Voting Booth?
      My favorite kind of desktop background is:

      Results (56 votes). Check out past polls.