StructFragment

A macro to create a duplicate of a struct with keys removed.

I mainly developed this macro to help with creating structs for interacting with the diesel create:

• original struct is the model, for reads from the database
• a struct with id removed, used for inserts into the database
• [coming soon] the ability to do this multiple times, allowing the definition of a struct fragment which would be received as a POST body.

Usage

Either providing a list of ignored fields:

#[derive(StructFragment)]
#[fragment_ignore_list = "id,updated_at"]
#[fragment_name = "DbUser"]
pub struct User {
    pub id: i32,
    pub full_name: String,
    pub email: String,
    pub updated_at: DateTime
}

Or adding #[fragment_ignore] to fields you don't want included.

#[derive(StructFragment)]
#[fragment_name = "DbUser"]
pub struct User {
    #[fragment_ignore] pub id: i32,
    pub full_name: String,
    pub email: String,
    #[fragment_ignore] pub updated_at: DateTime
}

Useful tools

• Provides the final expanded result of a macro, good for visualising what's actually happening: https://github.com/dtolnay/cargo-expand