Basic rules of decent Perl programming


    * Use the -w switch on the she-bang line.  When using this switch, Perl
      will complain about variables only used once, undefined filehandles
      etc.  Read the perlrun manual page for further information.  We can
      consider the -w switch as Golden Rule #1.

    * "use strict;" The strict pragma will enforce you to write more
      bullet-proof programs.  You have to predeclare your variables, avoid
      bare-words etc.  More on it in perldoc strict. "use strict;" is Golden
      Rule #2.

    * Check the return value of system calls.  Inform the user, what went
      wrong; you'll also save a lot of time when debugging.  The *$!*
      variable contains the last system call error.  Use clear and
      informative error messages, e. g. if you are trying to open a file,
      the error message should print out something like: "Cannot open
      '$filename' for reading: $!".  This is Golden Rule #3.

    * Always use the CGI module when writing a CGI script.  There is more
      than one way to do it, but not without using CGI.pm.

    * Use -T in your CGI scripts.  Do not trust any user input (e.g. web
      forms etc).  The perlsec pages will help you on your way.

    * Read perldoc perldiag.  Optionally you can use the diagnostics pragma
      in your programs.  It provides you even more debug messages than -w,
      and it will explain the errors, you get.

    * You may use the Fatal module.  It will replace functions with
      equivalents which succeed or die.  See the manual for details.

    * Use existing modules from CPAN.  Don't try to reinvent the wheel,
      unless you reinvent a rounder one.  You can download modules at
      "http://www.cpan.org/", and you can search for modules at
      "http://search.cpan.org/".

    * Use Perl's internal debugger.  It is intended to help you.  Read
      perldoc perldebug and save several hours and a lot of headache.

    * Make your source code easily readable.  Clarity is a measurement of a
      good Perl program.  Comment your code: after a year or two, you won't
      remember what did you do and why.  Comments also help others to
      understand and maintain your code.  Read the perlstyle pages.

    * Use Data::Dumper for printing complex data structures.

    * Use lexical scoping whenever possible.  Don't mess the global variable
      space.  If you accidentally use the same name elsewhere, you destroy
      existing values.

    * Read the perltrap pages.  It's necessary if you are coming from the
      AWK/sed/C world.

    * Take the advice of experienced Perl coders.

    * Always read the fine manuals.  And remember: there is more than one
      way to do it.


AUTHOR

    (C)opyright: Peter BARABAS <z0d @ @ artifact . . hu>, 2002.  All
    (R)ights reserved.