#created_by

🏭 Macro

#[created_by($struct_type)]

This macro is a simple way to implement the Creatable<T> trait for a custom structure you want to use as parameters when creating a new entity. Today, this macro is just a convenient way to implement the Creatable<T>; however, in the future, it may be extended to support more features which are common for creation parameters.

📝 Macro Example:

use repox::Entity;

#[derive(Debug, Clone, PartialEq, Entity)]
#[created_by(PostParams)]  // <- this structure can be used to create new
pub struct Post {          //    Post entities for supporting repositories
    pub id: u64,
    pub author_id: u32,
    pub data: String,
}

#[derive(Debug, Clone)]
pub struct PostParams {
    pub author_id: u32,
    pub title: String,      // <- it will be on the repository to decide
    pub content: String,    //    how to use these fields to create a Post
}

// It can be used by repositories to create new entities
async fn create_sample_post(
    repository: &impl repox::CreateWith<Post, PostParams>,
    author_id: u32
) -> Result<Post, anyhow::Error> {
    repository.create_with(PostParams {
        author_id,
        title: "Sample Title".into(),
        content: "Sample content...".into(),
    }).await
}

🔬 Macro Details:

Here is the same example, but, without using the macro to show that there is no magic here and that this macro is just a convenient way to implement the Creatable<T> trait for a custom structure 🧙‍♂️.

use repox::Entity;

#[derive(Debug, Clone, PartialEq, Entity)]
pub struct Post {
    pub id: u64,
    pub author_id: u32,
    pub data: String,
}

#[derive(Debug, Clone)]
pub struct PostParams {
    pub author_id: u32,
    pub title: String,
    pub content: String,
}

// without the following impl the `create_sample_post`
// would not compile since `CreateWith<T, P>` requires
// that `P` be `Creatable<T>`
impl repox::Creatable<Post> for PostParams {}

// It can be used by repositories to create new entities
async fn create_sample_post(
    repository: &impl repox::CreateWith<Post, PostParams>,
    author_id: u32
) -> Result<Post, anyhow::Error> {
    repository.create_with(PostParams {
        author_id,
        title: "Sample Title".into(),
        content: "Sample content...".into(),
    }).await
}