This document introduces several useful Rust libraries for implementing common patterns like new, getters, builders, and more easily through derives. It also presents libraries for treating bools like Options/Results and for chaining constructor calls. The author is looking to hire engineers.

1. Rust のちょっと便利なライブラリを使ってみる
下町.rs #2

2. だれですか？
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IgnorantCoder
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3. 少しだけサービスのご紹介

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● 枠がほしいんじゃなくて決済したいだけなのに…
● できあがったものも利便性がうんちゃかかんちゃか…

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6. 本題
社内で利用している便利ライブラリ紹介

7. derive_new
newを実装してくれる便利なやつ (https://docs.rs/crate/derive-new)

8. 既存コード
pub struct User {
name: String,
gender: Gender,
age: Option<u16>,
}
impl User {
pub fn new(
name: String,
gender: Gender,
age: Option<u16>) -> Self
{
Self { name, gender, age }
}
}
pub enum Gender {
Male,
Female,
Bigender,
Genderfluid,
Agender,
Demigender,
}
impl Gender {
pub fn new_male() -> Self {
Gender::Male
}
pub fn new_female() -> Self {
...

9. derive_new
#[derive(new)]
pub struct User {
name: String,
gender: Gender,
#[new(value = "None")]
age: Option<u16>,
}
#[derive(new)]
pub enum Gender {
Male,
Female,
Bigender,
Genderfluid,
Agender,
Demigender,
}
コードが減った！

10. derive_getters
getterを実装してくれる便利なやつ (https://docs.rs/crate/derive-getters)

11. 既存コード
pub struct Deal {
id: uuid::Uuid,
value: bigdecimal::BigDecimal,
currency: Currency,
}
impl Deal {
pub fn amount(&self) -> &bigdecimal::BigDecimal {
&self.value
}
pub fn currency(&self) -> &Currency {
&self.currency
}
}

12. derive_getter
#[derive(Getters)]
pub struct Deal {
#[getter(skip)]
id: uuid::Uuid,
#[getter(rename = "amount")]
value: bigdecimal::BigDecimal,
currency: Currency,
}
コードが減った！

13. derive_builder
builderを生み出してくれる便利なやつ (https://docs.rs/crate/derive_builder)

14. 既存コード
pub struct User {
id: uuid::Uuid,
first_name: String,
last_name: String,
age: Option<u16>,
}
#[derive(Default)]
pub struct UserBuilder {
id: Option<uuid::Uuid>,
first_name: Option<String>,
last_name: Option<String>,
age: Option<u16>,
}
impl UserBuilder {
pub fn id(self, value: uuid::Uuid) -> Self {
Self { id: Some(value), ..self }
}
pub fn first_name(self, value: String) -> Self {
...

15. derive_builder
#[derive(Builder)]
#[builder(pattern = "owned")]
pub struct User {
id: uuid::Uuid,
#[builder(setter(into))]
first_name: String,
#[builder(setter(into))]
last_name: String,
#[builder(setter(into), default)]
age: Option<u16>,
}
コードが減った！

16. derive_more
いろいろを生やしてくれる便利なやつ (https://docs.rs/crate/derive_more)

17. 既存コード
#[derive(PartialEq, Debug)]
pub struct Amount(i32);
impl std::fmt::Display for Amount {
fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
write!(f, "Amount: {}", self.0)
}
}
impl std::convert::From<i32> for Amount {
fn from(value: i32) -> Self {
Self(value)
}
}
...

18. derive_more
use derive_more::{Add, Display, From, Into, Sub};
#[derive(PartialEq, Debug, Add, Sub, Display, From,
Into)]
#[display(fmt = "Amount: {}", _0)]
pub struct Amount(i32);
コードが減った！

19. 気持ちよくかけるやつ

20. boolinator
boolをOptionとかResultみたいに (https://docs.rs/boolinator)

21. boolinator
use boolinator::Boolinator;
#[derive(PartialEq, Debug)]
pub enum ErrorType {
OhMyGod,
}
assert_eq!(Some(5), true.as_some_from(|| 5));
assert_eq!(None, false.as_some_from(|| 5));
assert_eq!(Ok(()), true.ok_or_else(|| ErrorType::OhMyGod));
assert_eq!(
Err(ErrorType::OhMyGod),
false.ok_or_else(|| ErrorType::OhMyGod)
);

22. apply
ok wrappingとかがうざい人むけ (https://docs.rs/apply)

23. apply
use std::sync::{Arc, Mutex};
let counter = Arc::new(Mutex::new(0));
use std::sync::{Arc, Mutex};
let counter = Arc::new(Mutex::new(0));
use std::sync::{Arc, Mutex};
use apply::Apply;
let counter = 0
.apply(Mutex::new)
.apply(Arc::new);
うざい
うざくない

24. エンジニア募集中！！！！！
@IgnorantCoder
https://github.com/IgnorantCoder/try-rust-libraries