Exercises, examples and other material relating to training module P219. This topic is presented on public courses Perl Programming, Perl for Larger Projects, Perl bootcamp, Learning to program in Perl, Perl Programming

There's much more to Perl than just the basic language; it comes with a rich set of modules built in to the distribution, and there's a further huge library available (The CPAN). Documentation is available in the Perl download, on line, and in a wide variety of books, and if you're looking for more interactive assistance there are forums, news groups, and chat rooms. There are even Perl user groups that meet around the world.

"Perl - I didn't know you could do that"

Articles and tips on this subject		updated
712	Why reinvent the wheel 1. Because you feel you can do better. 2. Because you've nothing else to do and you want to be busy when your boss walks by. 3. Because it's so much more fun re-inventing the wheel than using someone else's. 4. Because you can learn from your experience. 5. Because you didn't realise that someone ...	2012-10-01
3377	What do I mean when I add things in Perl? Some things have a natural concept of addition. And of multiplication. You can add numbers - 5 + 7 gives 12. You can add strings of text - "Hello " + "World" = "Hello World". You can add day trippers to a train and get a busier train (and add too many and you'll get an overcrowded unhappy train, ...	2011-08-03
3101	The week before Christmas The canal at Devizes earlier today as we passed through. You'll see from the ice that we weren't passing through by boat, nor was anyone else From the Perl for larger projects training course - a diagram to illustrate the problem of "diamond relationships". This is where a module "a" loads a module ...	2010-12-24
3009	Expect in Perl - a short explanation and a practical example Around 20% of delegates on our Tcl Courses are using Tcl because of the Expect package that extends it to "choreograph" interaction with other systems and processes, and yet the Expect module in Perl (Expect.pm) is decidedly niche and we cover it on our Perl for Larger Projects course only on request. ...	2010-10-22
2931	Syncronise - software, trains, and buses. Please! To get from my home to the Divisional Police HQ on another side of Melksham, I can take a five minute bus ride on the X72 or 272, change at the Market Place onto the 234 or X34, and ride for another five minutes. So for a meeting at 19:00, I can catch a bus just after 18:00 to be there in good time, ...	2010-08-24
2427	Operator overloading - redefining addition and other Perl tricks What does addition actually mean? It means different things depending on what you're adding together, and in Perl you can redefine additions - and other operators - on objects of types which you define. This is known as operator overloading, and there's a complete code example here. So ... how do ...	2010-06-20
2234	Loading external code into Perl from a nonstandard directory Here's a piece of Perl code that loads in an external module. push(@INC, "/var/opt/OV/bin/OpC/monitor"); eval { require "monitor_utils.pm"; }; if ($@) {   print STDERR "could not load monitor_utils.pm: $@\n";   exit 1; } It comes from a delegate's existing application, and is worthy ...	2009-06-12
2229	Do not re-invent the wheel - use a Perl module "If you think 'surely someone has done this before', you're probably right ... and in Perl, you'll find the resource you need available as a module on your system, or if it's not quite to common, on the CPAN". I was reminded of this advise today, when I got involved with web site checking ... and rather ...	2009-06-12
737	Coloured text in a terminal from Perl If you're looking to do something in Perl and the back of your mind tells you that, surely, someone's done this before then there are two things to note: • Someone probably HAS and • It's probably available on the CPAN or as a built in module. Thus when I was asked the question "How do I get ...	2008-12-09
1865	Debugging and Data::Dumper in Perl I'll admit it - I'm not a great fan of debuggers, preferring to write well structured code, and check it out with a few test / intermediate print statements. You'll often find I code:     $trace and print (something); in Perl, and this allows me to add a line     $trace=1; at ...	2008-11-01
1863	About dieing and exiting in Perl If you want to end a program in Perl, you can get out quickly enough with an exit function call. But that's probably just a part of what you'll be wanting to do - you'll be wanting to generate an error message on the error channel (STDERR) too, and perhaps to tell your user rather more about why the ...	2008-11-01
1391	Ordnance Survey Grid Reference to Latitude / Longitude I've already written about conversion of postal addresses to latitude and longitude using Google's interface - but what is I want to convert the Ordinance Survey's grid references into latitude and longitude? Google's interface doesn't support the OS units - and in any case it's "just" a a calculation. ...	2008-08-30
86	Talk review - Idiomatic Perl, David Cross David Cross's talk on Idiomatic Perl was excellent. I know of Dave from his book Data Munging with Perl so I had some idea of what he was going to be covering. Now - I've been training in Perl for a number of years, so I didn't expect to learn much technically new, but I did expect to pick up nuances, ...	2008-05-11
1444	Using English can slow you right down! When you're programming and you assign a variable, that's usually a single result. For example (we're talking Perl in these examples) $position = $record % $pagelength; However, there are often side effects of an action which you might want to make later use of too. For example: $postcode = ($pc ...	2007-11-25
1235	Outputting numbers as words - MySQL with Perl or PHP Oracle's in_char function lets you convert numbers into a text string, but it's an unusual facility to have as as built-in; there's no such facility (as far as I know) in MySQL but you can get around this easily enough within your controlling application - the Nums2Words module on the CPAN (in Perl), ...	2007-06-17
1219	Judging the quality of contributed Perl code So you're going to download a module from Perl's CPAN. Good - you've learnt the first rule which is to re-use code that someone else has written, and NOT write your own. But then you have another conundrum - which of the dozens of modules that look as if they should be suitable should you download ...	2007-06-07
760	Self help in Perl Perl's POD (Plain Old Documentation) system provides the programmer with the ability to add user documentation into his programs - allowing a single source file to include: * The program itself * Comments for future programmers who read the source * Documentation for the user Convertors such as pod2html ...	2006-06-15
112	Avoid the wheel being re-invented by using Perl modules "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 ...	2006-06-05

ac1	perl -w / turning warnings on and off
colpert	printing coloured text in your terminal window
dadu
mod_demo	Use of standard modules
stx	croak - like die, but reports line in calling package
togridref	Latitude / Longitude to UK Ordnance Survey Grid Reference convertor.
tolatlong	UK Ordnance Survey Grid Reference to Latitude / Longitude convertor
wholenumbers	The integer pragma illustrated

Perl - find it on the CPAN!