Struct Topic 

pub struct Topic<T: Message> { /* private fields */ }

A type-safe topic with an associated message type

This is the core abstraction that enables compile-time type safety for pub/sub. Topics are defined as constants and carry type information via phantom types.

Type Safety Guarantee

The compiler ensures that:

• Subscribe returns the correct message type
• Publish accepts only the correct message type
• No runtime type confusion is possible

Example: Defining Topics

use mecha10::topics::Topic;
use mecha10::messages::Image;

// Simple topic definition
pub const CAMERA_RGB: Topic<Image> = Topic::new("/sensor/camera/rgb");

// Custom message type
#[derive(Serialize, Deserialize)]
struct MyMessage {
    value: f32,
}

pub const CUSTOM: Topic<MyMessage> = Topic::new("/custom/topic");

Example: Using Topics

// Type is inferred as Receiver<Image>
let mut images = ctx.subscribe(sensor::CAMERA_RGB).await?;

while let Some(image) = images.recv().await {
    // image is type Image
    println!("Image: {}x{}", image.width, image.height);

    // Compiler ensures we publish the right type
    ctx.publish_to(sensor::CAMERA_RGB, &image).await?;

    // This would be a compile error:
    // ctx.publish_to(sensor::CAMERA_RGB, &laser_scan).await?;
    //                                      ^^^^^^^^^^^ expected Image, found LaserScan
}

Implementations

impl<T: Message> Topic<T>

pub const fn new(path: &'static str) -> Self

Create a new typed topic

This is a const function, so topics can be defined as constants.

pub const fn path(&self) -> &'static str

Get the topic path

pub fn as_str(&self) -> &'static str

Get the topic as a string (for compatibility)

Trait Implementations

impl<T: Message> Clone for Topic<T>

fn clone(&self) -> Self

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl<T: Message> Debug for Topic<T>

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl<T: Message> Display for Topic<T>

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl<T: Message> Copy for Topic<T>