Adding style to perl code

Perl has always been my favourite command line and web programming language. There is nothing Perl can't do. The Perl language combined with the large quantities of modules on CPAN (developed by some of the best programmers on the planet) makes it the kitchen sink of programming languages.

I like to make my code as easy to read as possible. Nothing irks me more than a jumble of spaghetti code with indents and curly braces everywhere. I admit that there are times when a solution to a complex problem comes to me, and I become more concerned with getting my ideas down than with following style rules. But after I have my thoughts properly coded, I want to go back and clean things up a bit. That's where perltidy comes in.

What is Perl::Tidy?

Perltidy is a Perl script which indents and reformats Perl scripts to make them easier to read.

The CPAN module, written by Steve Hancock, makes the functionality of the perltidy utility available to other Perl scripts. That means you can write your script for your own Perl-style needs. I prefer to use the utility.

Installation

Installing Perl::Tidy on OS X is relatively easy. Use the sudo command from the Terminal to run the CPAN command line utility. You need to be logged into an account with administrator privileges. This will pull down and install from CPAN, all the necessary code for using perltidy.

Using perltidy

Once the module has been installed (the utility is placed in /usr/bin ), you can use the command line utility just like any command in Terminal. Perltidy has several command line switches to modify its behaviour. The default styling works well enough for me. To use the command line utility, open up a Terminal window and type :~ perltidy -b /path/to/your/code.pl

I used the -b switch to tell perltidy to create a backup of my script before doing its work. I want a copy just in case something goes wrong. Perltidy does its thing and then exits. If errors are found, e.g. a missing curly brace, perltidy will let you know and create an error file that contains more information about the problem.

Perltidy will take this code:

my %var = { name => ‘khurt’, last => ‘williams’, location => ‘Princeton’, height => ‘164cm’, weight => ‘64 kg’ }; foreach my $key ( sort keys %var ) { printif( “%s:%sn”, $key, $var{$key} ); } #this prints the values in the hash

And turn it into this code:

my %var = {
    name     => 'khurt',
    last     => 'williams',
    location => 'Princeton',
    height   => '164cm',
    weight   => '64 kg'
};
foreach my $key ( sort keys %var ) {
    printif( "%s:%sn", $key, $var{$key} );
}    #this prints the values in the hash

Useful perltidy command:

: ~ perltidy -html -pre code.pl

This will create an HTML snippet with only the PRE section to code.pl.html. This is useful when code snippets are formatted for inclusion in a larger web page (such as a blog).

To learn more about perltidy, type "man perltidy" into Terminal to see the manual page. Prepare to be overwhelmed. Perltidy is feature-rich.

AJAX Toolkits

Ajaxian conducted a recent survery on Ajax toolkits/frameworks. The "winner" was Prototype ( a new one to me ) which is a Ruby-based framework. Wow! I did not realise there were so many AJAX frameworks out there! I use Sajax ( it is simple ) and have been experimenting with Backbase ( too complex for me ). PHP turns out to be the most popular server-side web development platform. Good news for me. I have been using PHP more often than Perl now.  I have been using the Sajax toolkit for a few months now and I really like it.  True to it's name it is simple to setup and use.  I tooled around with Backbase but...the learning curve and complexity required more time than I have patience for.  I also very quickly tired the Dojo AJAX toolkit/framework.  I think that one has potential ( easy to use and lots of features ) and I may come back to it later.