lee-orr / bevy-state-match-prototype

Caution

This Repository is no longer maintained, as the associated PR has been closed. It's archived to prevent breaking dependent projects, but should not be used.

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Bevy State Matching Prototype

This crate is an implementation of the State Pattern Matching - Alternative PR as a third party crate, to provide access to test out the feature in 0.12 before it gets merged in for, hopefully, 0.13.

NOTE: much of the code is directly copied and pasted from the Bevy repository, and while I implemented the changes in the PR - there are many others who were involved in creating the original code. As such, despite this being a 3rd party repository, I'd consider all the code here to be Bevy's rather than mine - I'm just providing early access to this API.

Differences from the PR

Due to being a 3rd party crate, there are some added limitations on what we can do, which result in some API differences:

• we can't auto-implement IntoSystem for state matchers. As a result, we have opted to add a run_in<S: States, Sm: StateMatcher<S>>(Sm) to all implementors of IntoSystem - that way it'll just be a search and replace when migrating to 0.13 - assuming the API remains intact. In addition, I added an and_then function to StateMatcher<S> directly, but it won't support conditions - only other matchers. If you want both state matchers and other conditions, you will have to chain run_in and run_if commands.
• we can't replace existing types with the same name - so the enum version of NextState has been renamed NextMatchableState
• we can't replace the existing add_state with one that triggers the Entering & Exiting states when states change, or uses the updated NextMatchableState implementation, so we added an add_matchable_state method for that purpose.

Installation

To install, you currently need to specify the github repo in Cargo.toml:

[dependencies]
bevy = "0.12",
bevy_state_matching_prototype = { git = "https://github.com/lee-orr/bevy-state-match-prototype" }