This library contains the ECS used by the Mischief Game Engine.

No LLM / AI was used in making Mischief. Now and forever.

Mischief has various meanings. It can be a group of rats. Or it can refer to being naughty and playful.

This Mischief, however, is an open-source ECS Game Engine! In other words...

Mischief :: Entity -> Component c => System ()

Mischief takes great inspiration from Bevy and Flecs, and was written in 100% Haskell, taking advantage of its great ergonomics and strong type system. It is a refreshing spin on the functional and data-driven paradigms.

Package

This package contains only mischief-ecs, the ECS at the core of Mischief. Other packages, such as mischief-input, mischief-assets, mischief-render are planned, but haven't yet been developed to the same level as the ECS itself.

Design Goals

These are the main design goals of Mischief:

• Ergonomic and Accessible. Mischief's main purpose is to provide a very clean, intuitive, inherently opinionated, high-level API. This is the main way we differentiate ourselves from other ECS's. Learning to use Mischief should be a painless and intuitive process.
• Functional and Data Driven. We strive to find a balance between functional programming and data-driven design. These are two concepts that don't interact very often, but that both stand at the core of Msichief.
• Modular. Mischief is meant to be modular, allowing you to plug packages in and out, whether they are made by us or a third party.

Highlights

Here are some highlights of Mischief:

• Highly Dynamic . Want to disable a system? Despawn it!
• Fancy Queries. Complete with transitive queries and filters.
• Quasi-Queries. Scripting language for writing queries.
• Rich Systems. Monadic Systems? Yes please.
• Book. Mischief has its very own book! See below.
• Relationships. Bob Likes Charlie.
• Events.
• And much much more..

Performance

Performance-wise, Mischief still has a long way to go; there are many easy performance gains that we have just been too busy to implement, as we've been mostly focusing on ergonomics, modularity, and ease-of-use. This is a pretty strong Archetype ECS however, and it is possible to bring it to about the same asymptotic performance as Bevy or Flecs, although there will probably always be a layer of indirection (or 20) that makes it a bit slower, due to the high-level, boxed, nature of Haskell.

In order to learn how to use Mischief, you can read through the official book:

1. Startup Guide
2. Coding a Dungeon Game
3. App and Plugins
4. Components
5. Relationships
6. Queries
7. Systems
8. Events and Messages