Macro aframe::system_def

macro_rules! system_def {
    (
        $(schema: $schema:expr,)?
        $(init: $init:expr,)?
        $(pause: $pause:expr,)?
        $(play: $play:expr,)?
        $(tick: $tick:expr,)?
        $(properties: $($fn_name:ident: $func:expr),*)?
    ) => { ... };
}

Top-level macro to define systems. Usage resembles struct creation syntax. The js! macro is available for writing inline javascript, and returns a js_sys::Function object. This macro calls into on expressions passed into the fields expecting function, allowing the js! macro to be used as a catch-all. Takes the optional fields described in the table below.

field	syntax explanation	description
schema	A hashmap containing string keys and ComponentProperty values. Recommend the maplit crate	Describes component properties
init	JsValue created from a js_sys::Function()	Called on initialization
pause	JsValue created from a js_sys::Function()	Called when the entity or scene pauses
play	JsValue created from a js_sys::Function()	Called when the entity or scene resumes
tick	JsValue created from a js_sys::Function(time, timeDelta)	Called on each tick or frame of the scene’s render loop
properties	name: JsValue, …	Additional comma-separated functions or data with any valid name may be specified

All parameteres are optional, although the order must be exactly as shown. schema should be a HashMap with string keys and AframeProperty values. The rest are strings containing javascript code. A js! macro is provided to allow inline javascript code to be included in the Rust code (See the docs for the js! macro for caveats and limitations). Here’s an example:

// Example: 
let some_system = system_def!
(
    schema: hashmap!
    {
        "some_float" => AframeProperty::float("number", None),
        "some_text" => AframeProperty::string("string", Some(Cow::Borrowed("init")))
    },
    init: js!
    (
        this.data.some_float = 1.0; 
        this.data.some_text = "I'm a bit of text";
    ),
    tick: js!
    (time, delta =>>
        this.data.some_float = this.data.some_float + 1.0;
    ),
    pause: js!(this.data.some_text = "paused!";),
    play: js!(this.data.some_text = "playing!";),
    properties:
        reset_me: js!(this.data.some_float = 0.0;)
);
unsafe
{
    some_system.register("system_name");
}