About

This is a rust library to derive "Builder" methods for arbitrary rust structs. It relies on the Macros-1.1 RFC and currently only works with the nightly rust build.

How to use

Setup

toml [dependencies] smelter = { git = "https://github.com/Ivan1931/smelter" }

Add the following to the file in which you with to use smelter. ```

![feature(procmacro, customattribute)]

[macro_use]

extern crate smelter; ```

Then just add #[derive(Builder)] above your struct,

Simple Example with Generated Code

Smelter

Generated Code

#![feature(proc_macro, custom_attribute)]

#[macro_use]
extern crate smelter;

#[derive(PartialEq, Debug, Builder, Default)]
pub struct Point {
    pub x: u32,
    pub y: u32,
}

# [ allow ( unused_attributes ) ]
# [ derive ( PartialEq , Debug , Default ) ]
pub struct Point {
    pub x: u32,
    pub y: u32,
}

# [ allow ( dead_code ) ]
impl Point {
    pub fn x(self, __value: u32) -> Point {
        Point { x: __value, ..self }
    }

    pub fn y(self, __value: u32) -> Point {
        Point { y: __value, ..self }
    }

    pub fn x_mut(&mut self, __value: u32) -> &mut Point {
        self.x = __value;
        self
    }

    pub fn y_mut(&mut self, __value: u32) -> &mut Point {
        self.y = __value;
        self
    }
}

Usage of Code

rust // somewhere in your code base //... let p1: Point = Default::default().x(1).y(2); let mut p2: Point = Default::default(); p1.x_mut(1).y_mut(2); assert_eq!(p1, p2); //...

With a custom field prefix

Smelter

Generated Code

#![feature(proc_macro, custom_attribute)]

#[macro_use]
extern crate smelter;
#[derive(PartialEq, Builder, Default, Debug, Clone)]
#[smelter(prefix="with_")]
pub struct User {
    pub uid: u64,
    pub email: String,
    pub alias: String,
    pub friends: Vec,
}

# [ allow ( unused_attributes ) ]
# [ smelter ( prefix = "with_" ) ]
# [ derive ( PartialEq , Default , Debug , Clone ) ]
pub struct User {
    pub uid: u64,
    pub email: String,
    pub alias: String,
    pub friends: Vec,
}
# [ allow ( dead_code ) ]
impl User {
    pub fn with_uid(self, __value: u64) -> User {
        User { uid: __value, ..self }
    }
    pub fn with_email(self, __value: String) -> User {
        User { email: __value, ..self }
    }
    pub fn with_alias(self, __value: String) -> User {
        User { alias: __value, ..self }
    }
    pub fn with_friends(self, __value: Vec) -> User {
        User { friends: __value, ..self }
    }
    pub fn with_uid_mut(&mut self, __value: u64) -> &mut User {
        self.uid = __value;
        self
    }
    pub fn with_email_mut(&mut self, __value: String) -> &mut User {
        self.email = __value;
        self
    }
    pub fn with_alias_mut(&mut self, __value: String) -> &mut User {
        self.alias = __value;
        self
    }
    pub fn with_friends_mut(&mut self, __value: Vec) -> &mut User {
        self.friends = __value;
        self
    }
}

Usage of Code

```rust // ... somewhere in your code let mut u1 = User::default(); // ... u1.withemailmut("cardboardbox@example.com".tostring()) .withaliasmut("Cardboard box".tostring()) .withuidmut(10u64);

// ... somewhere else let u2 = User::default() .withemail("filecabinate@example.com".tostring()) .withalias("File Cabinate".tostring()) .with_uid(10u64); ```

More Examples

For more examples see the test.rs

Caveats

Currently this library will only work on a nightly build of rust.

It relies on macros 1.1