As we continue to build Tau Station, the free-to-play narrative sci-fi MMORPG (what a mouthful!), we find our code base is getting larger and larger. As with any large codebase, we've found ourselves sometimes mired in technical debt and need a way out.

One simple hack I wrote has saved so much grief with this process. I can run this from the command line:

bin/dev/rename-module.pl Veure::Old::Module::Name Veure::New::Module::Name

And it automatically renames the module for me, updates all references to it, creating directories as needed, renaming test classes built for it, and uses git.

It's fair to say that at our consulting company, we work with many clients who use Perl heavily. The "preamble" of their Perl code is either an ad-hoc mixture of features, or stock boilerplate like this which gets cut-n-pasted all over the place:

use strict;
use warnings;
use v5.24;
use feature "signatures";
no warnings 'experimental::signatures';
use utf8::all;
use Carp;

Both of those approaches are dead wrong. The "ad hoc" pragma list means it's hard to be sure what features are or are not available. The "standard boilerplate" approach means cutting-n-pasting and then hating yourself when you have to change that standard boilerplate.

Modern::Perl is a nice middle ground for avoiding this, but it may not be the features you want. For example, our free-to-play narrative browser game, Tau Station, doesn't use the C3 MRO because we don't use multiple inheritance (note: we enforce C3 on our DBIx::Class classes, of course).

Instead, we have our custom boilerplate, wrapped up in Veure::Module.

At The Perl Conference in Washington DC, I'll be giving a talk on Modeling a Universe in Perl. For previous versions of this talk, people have asked for more information about how we model complex actions in a (mostly) declarative manner. For example, here's the code for purchasing a clone:

It's the Steps() function which is our declarative code. As you might imagine, there are tons of actions which might require that you be in a particular area, or have credits removed from your wallet, so the Area and Wallet lines can be dropped into any Steps() function anywhere throughout our code. But people want to know how this works. In reality, it's pretty simple.

I wrote about using the Perl debugger with Moose. In that post, I showed how to use DB::Skip to make it easier to use the Perl debugger with Moose and other modules whose guts you don't want to wade through.

Today's debugger hack will make using the debugger with DBIx::Class much easier.

If you've been following our progress with Tau Station, you know we're creating a science fiction universe in Perl for people to enjoy. As of this writing, the time in Tau Station is 194.10/51:647 GCT.

"GCT" stands for "Galactic Coordinated Time" and that's a variant of metric time. As a software developer, I wish we had that in the real world, but alas, we don't.

The GCT time listed above is roughly 194 years and 10 days after the "Catastrophe" (an apocalyptic event that effectively serves as our "epoch"). There are 100 days in a year, 100 "segments" in a day (14.4 minutes each) and 1000 units in a segment (.864 seconds each).

I love the fact that figuring out the display time for GCT is this simple:

my $days = sprintf "%9.5f" => $seconds_since_catastrophe / $second_in_a_day;
$days =~ m{^(?<year>\d+)(?<day>\d\d)\.(?<segment>\d\d)(?<unit>\d\d\d)}a;
my $gct = "$+{year}.$+{day}/$+{segment}:$+{unit} GCT";

Due to imprecision in normal dates, we don't get an exact round-trip conversion between regular DateTime objects and GCT, but so far we've not found them more than a second off.

Figuring out durations (D0.00/12.500) is similarly simple:

my $days = sprintf "%9.5f" => $duration_in_seconds / 86400;
$days =~ m{^(?<years>\d+)(?<days>\d\d)\.(?<segments>\d\d)(?<units>\d\d\d)}a;
my $duration => "D$+{years}.$+{days}/$+{segments}:$+{units}";

Of course, since that means we often need to know the total number of seconds, we have this nasty bit of code to figure that out:

sub period (%args) {
    my $seconds = delete $args{seconds} // 0;
    $seconds += ( delete $args{minutes}  // 0 ) * 60;
    $seconds += ( delete $args{hours}    // 0 ) * 3600;
    $seconds += ( delete $args{days}     // 0 ) * 86400;

    # solar year
    $seconds += ( delete $args{years}    // 0 ) * 31_556_925.97474;
    $seconds += ( delete $args{units}    // 0 ) * .864;
    $seconds += ( delete $args{segments} // 0 ) * 864;
    if ( keys %args ) {
        my $unknown = join ', ' => sort keys %args;
        croak("Unknown keys to Veure::Util::Time::period: $unknown");
    }
    return round($seconds);
}

Metric time is lovely and easy. Regular time sucks.

I really wanted to write a DBIx::Class inflator to use GCT objects instead of DateTime objects, but found too many assumptions about the use of DateTime in the DBIx::Class code, so we scrapped that bit. Darn shame.

There's a problem that I've seen on every team I've worked with that uses git. Because at Tau Station we're fairly merciless about technical debt--which makes the code base pretty sweet to work with--we take all technical debt issues seriously on the theory that once we launch, it may be too late to clean up (a silly idea in theory, but a prevalent one in practice).

The following technical debt issue is actually causing us a problem, though it's more of a process problem than a technical one:

05:35:02 (master) ~/veure $ git branch -a | wc -l
     272

Wow! We have 272 branches? Most of those are are long merged or abandoned. We've discovered that there are a couple of them which got overlooked (I'm tempted to blame github's poor PM tooling, but it's a lousy craftsman who blames his tools). We tried asking devs to find all of their remote branches and review them and delete them, but that turned out to be a rather daunting task and they're still missing branches.

Now, with a simple Perl script, we have a solution.

I haven't blogged lately because of ridiculous amounts of work on the Tau Station MMORPG (the game formerly known as Veure and written almost entirely in Perl). I had reluctantly stopped my last contract with ZipRecruiter because of surgery (long story, but not life-threatening) and then experiencing the joy of physiotherapy. Near the end of physio, we decided as a company to make a serious push on Tau Station and bring it to alpha. Here's an update.

I'm back from Romania and had a lovely time at YAPC::EU, er, The European Perl Conference, er, or this:

I unveiled that suggested logo at my opening keynote only to discover that many Perl devs had no idea what I was talking about. My sense of humor is shouting "get off my lawn."

However, I gave a lightning talk announcing Veure, including the game's name and blog! Veure is officially known as Tau Station and sign up for our newsletter to find out more, including keeping up with the alpha. Or just read our blog to see what's happening with it (but you really want to sign up for that newsletter).

Many thanks to Evozon for hosting a great conference!

I recently wrote about Veure's test suite and today I'll write a bit about how we manage our database. Sadly, this will be a long post because it's a complicated problem and there's a lot to discuss.

When I first started Veure, I used SQLite to prototype, but it's so incredibly limited that I quickly switched to Postgres. It's been a critically important decision, but I want to take a moment to explain why.

All software effectively has four "phases" which amount to:

1. Initialization
2. Input
3. Calculation
4. Output

Note that we could rewrite the above as:

1. Initialization of data
2. Input of data
3. Calculation of data
4. Output of data

Notice a pattern?

Yeah, I thought so. There are all sorts of areas where we could get things wrong in software, but the further down the stack(s) you go, the more care you need to take because the more damaging bugs can be. Data storage is often pretty low in your stack and you don't want to get this wrong. So what happens?

Over on Perlmonks I wrote that you should probably use this:

say join '', @array[2,4];

Instead of this:

local $" = '';
say "@array[2,4]";

And my reasoning being:

Why is that better? Because nobody knows what $" is, but everyone knows what join() is. Always write your software to be as readable as possible :)

I received a couple of upset replies along the lines of "Perl devs should be allowed to write Perl!" While I generally agree with that sentiment -- I had no problem with the array slice, for example -- I think the replies came, in part, because I had answered too quickly. I clarified what I meant, but I thought I should explain it here, too, because too many people reach for those punctuation variables.