Tutorial-writing and Attributes galore ¶

- July 5, 2022

It has been a while since I wrote anything for the dev blog of Evennia, the MU creation system - so it's about time!

It's been a busy spring and early summer for me, with lots of real-life work going on away from Evennia land. But that hasn't meant activity on the Evennia code base has slowed!

Many eyes on Evennia 1.0-dev

Earlier this year I invited people to try the Evennia develop branch - what will become Evennia 1.0. A lot of bold beta-testers have since swapped to using the 1.0 branch. While there are plenty of issues being reported, most seem pretty happy about it so far. As mentioned in earlier dev blogs, Evennia 1.0 has a lot of improvements and new features!

As part of this, the amount of PRs being made against develop branch has increased a lot, with awesome community members stepping up to fix bugs and even address long-standing annoyances. This includes everything from big improvements in ANSI parsing, fixes to the 1.0 FuncParser, RPSystem contrib optimizations and much more - the list of closed PRs is long.

Another big part are everyone helping to answer questions in chat and suggesting improvements to the community in general. Thanks everyone!

The upcoming beginner tutorial

On my end, I'm working on the Beginner Tutorial for the new 1.0 documentation. This will be a multi-part tutorial where you get to make a little MUD game from scratch. It goes through the basics of Evennia all the way to releasing your little game and I hope it will help people get started. This will also lead to a new contrib - the evadventure package, which should (I plan) have everything the tutorial needs to run. This is useful for those that prefer picking apart existing code over reading about it.

The tutorial game itself is based on Knave, an light Old-School-Renaissance (OSR) tabletop roleplaying ruleset inspired by early editions Dungeons & Dragons. It's simple enough to fit in a tutorial but with enough wrinkles to showcase how to create some basic rpg systems in Evennia:

• Using Attributes (STR, DEX etc)

• Rules (dice rolls, advantage, contested rolls etc)

• Character generation (Knave chargen is mostly random, but it still showcases Evennia's menu system EvMenu).

• Inventory management and equipment (including limited storage as well as items worn or wielded).

• Turn-based combat system (menu based)

• • Attacking with wielded weapons (or spell rune)
• • Stunts to give you advantages for later turns or give enemies disadvantage for later turns
• • Using items for healing or other effects
• • Fleeing and chasing

• Alternative Twitch-based combat system (might be a stretch goal)

• NPCs with very simple AI, Death and respawn

• Simple Questing system with NPC quest givers and quest states

• A small example world (tech-demo)

I won't include how to make a Crafting system, since I've added a full Crafting contrib to Evennia 1.0 for devs to be inspired by or tear apart.

Some nice new things about Attributes

In general news, Evennia 1.0 will see two big improvements when it comes to Attributes.

AttributeProperty

This is a new way to write - and particularly initialize - Attributes. Traditionally in Evennia you need to initialize your object's Attributes something like this:

from evennia import DefaultCharacter



class Character(DefaultCharacter):

    def at_object_creation(self):

        self.db.strength = 10

        self.db.mana = 12

This still works. But with the new AttributeProperty you can now write it like this instead:

from evennia import DefaultCharacter

from evennia.typeclasses.attributes import AttributeProperty



class Character(DefaultCharacter):

    strength = AttributeProperty(10)

    mana = AttributeProperty(10)

This makes Attributes look more like Django fields, sitting directly on the class. They can also have category and all other values you'd expect. You can still access those Attributes like normal:

strength = char.db.strength

mana = char.attributes.get("mana")

But you can now also do just

strength = char.strength

mana = char.mana

directly (you'll need to be careful to not override any existing properties on objects this way of course).

An interesting feature of using an AttributeProperty is that you can choose to not actually create the Attribute under the hood unless the default changed:

class Character(DefaultCharacter):

    strength = AttributeProperty(10, autocreate=False)

    mana = AttributeProperty(10, autocreate=False)

When you now access char.strength you will get 10 back but you won't actually be hitting the database to load anything - it's just giving you the default. Not until you change the default will the actual Attribute be created. While this can be very powerful for optimization, note that you can of course not access such data via char.db or char.attributes.get either (because no Attribute yet exists). So this functionality can be confusing unless you know what you are doing. Hence autocreate defaults to True.

Saving Attributes with hidden database objects

This is one of those classical quirks of Evennia that many have encountered. While Evennia can save a lot of things in an Attribute, including database objects, it cannot do so if it doesnt know those database objects are there. This is fine if you are saving a list or a dict with objects in it - Evennia will go through it and make sure to serialize each db-object in turn.

But if you "hide away" your db-object you will be in trouble:

class MyStore:

    def __init__(self, dbobj):

        self.dbobj = dbjobj



char = Character.objects.get(id=1)

obj.db.mystore = MyStore(char)   # leads to Traceback!

This fails because we store char inside MyStore and there is no way for Evennia to know it's there and to handle it properly.

For the longest time, this was just a limitation you had to accept. But with Evennia 1.0-dev you can now help Evennia out:

from evennia.utils.dbserialize import dbserialize, dbunserialize



class MyStore:

    def __init__(self, dbobj):

        self.dbobj = dbobj

    def __serialize_dbobjs__(self):

        self.dbobj = dbserialize(self.dbobj)

    def __deserialize_dbobjs__(self):

        self.dbobj = dbunserialize(self.dbobj)



char = Character.objects.get(id=1)

obj.db.mystore = MyStore(char)   # now OK!

With the new __serialize_dbobjs__ and __deserialize_dbobjs__, Evennia is told how to properly stow away the db-object (using the tools from evennia.utils) before trying to serialize the entire MyStore. And later, when loading it up, Evennia is helped to know how to restore the db-object back to normal again after the rest of MyStore was already loaded up.

Moving forward ...

For Evennia 1.0, the tutorial-writing is the single biggest project that remains - that and the general documentation cleanup of our entirely rewritten documentation.

After that I will dive back in with the issues that has popped up during beta-testing of 1.0-dev and try to wrap up the most serious ones before release. Still some time away, but it's getting there ... slowly!

Into 2022 with thanks and plans ¶

- January 6, 2022

I didn't write an end-of-the year summary for 2021, so this first devblog of 2022 will also look back a bit at the past year. It also helps me get used to using this new blog platform I wrote about in the previous post.

On Evennia 1.0

Speaking of 2021, you may have noticed that there was no new versioned Evennia release last year. Last one was 0.9.5 back in 2020. This may make it seem like little is happening in Evennia-land ... but the fact is that while little has happened in master branch over the past year, all the more has been going on in Evennia's develop branch - the branch which will become Evennia 1.0.

Now, it's not really so good to have a development branch run so long. This is because in the interim people report errors in master branch that has since been resolved in develop. It's becoming more and more cumbersome to backport which means that master is not getting updated all that much right now.

Post 1.0, I'll likely switch to a faster release cycle, but at least for now, it has been hard to avoid, this is because I'm reworking the entire documentation site alongside the code, with new autodocs and tutorials. Releasing an intermediary version with some sort of mid-way documentation version is just not practical for me. So I hope you can be patient a bit further!

Soonish™, I hope to have finished the code changes needed for 1.0 and then I'll invite adventurous folks to use the branch more extensively while the docs are still in flux.

So what's still to do for Evennia 1.0?

This is the current TODO list.

The big one I'm currently doing is to refactor the contrib/ folder to have more structure (it has grown organically until now). After this, there are a series of bugs and minor features to do. I will also go back and address the low-hanging master branch bugs that haven't already been resolved in develop.

Most remaining points are then documentation fixes. Those will be handled in one go as the docs are finalized.

So ...

I won't/can't commit to a deadline for Evennia 1.0, but I'll keep chipping away at it as fast as I can. If you want things to move quicker you are more than welcome to join the other contributors that have chipped in with PRs over the past year. Check out the TODO list and consider investigating a bug or implementing a feature - some may be pretty straight forward.

... some thanks!

A big thanks to those that dropped an encouraing buck in my hat (aka patreon or with a one-time paypal donation) over the year. Everyone has different economical situations and I hope I've been very clear that noone should feel obligated to pay anything. But those of you that could and did - know that you have my thanks - it's very encouraging.

But - just as big thanks go out to everyone that contributed to Evennia in 2021! "Contribution" means so many things - we have the troopers that contributed code and made PRs (best Hacktoberfest yet!), but also those that dilligently reported bugs and pointed out problems as well as (and this is just as important) were active and helpful in the support chat and github discussion!

You guys make the community, that's all there is to it. Thanks a lot.

Now onward into this new, fresh year and towards that elusive Evennia 1.0 ...