Crate enum_update

enum-update

enum-update is a set of macros and traits for representing state changes as enums.

Note: enum-update is currently at v0.1.0 and is not at stable v1.0.0 yet. Overall functionality should stay the same, but trait and macro names may change between versions.

Adding enum-update to your project

Import enum-update into your project by running this command.

cargo add enum-update

All enum-update-derive macros are re-exported by enum-update. There is no need to manually add enum-update-derive to your project dependency list.

Macros

The following derive macros are provided by enum-update

Derive macro	Description
EnumUpdate	Creates a new enum representing updates to a struct
EnumUpdateSetters	Add setter methods to a struct that also return enums generated by EnumUpdate

Examples

EnumUpdate

Basic example

use enum_update::*;
#[derive(Debug, PartialEq, EnumUpdate)]
pub struct MyState {
    value: String,
    another_value: u32,
}
// `EnumUpdate` will generate:
// pub enum MyStateUpdate {
//     Value(String),
//     AnotherValue(String),
// }
// impl EnumUpdate<MyStateUpdate> for MyState {
//     fn apply(&mut self, update: MyStateUpdate) {
//         match update {
//             MyStateUpdate::Value(value) => {
//                 self.value = value;
//             },
//             MyStateUpdate::AnotherValue(another_value) => {
//                 self.another_value = another_value;
//             }
//         }
//     }
// }
let mut state = MyState {
    value: "initial_string_value".to_string(),
    another_value: 123,
};
let first_change = MyStateUpdate::Value("new string value".to_string());
state.apply(first_change);
assert_eq!(state, MyState {
    value: "new string value".to_string(),
    another_value: 123
});

EnumUpdateSetters

Basic example

use enum_update::*;
#[derive(Debug, PartialEq, EnumUpdate, EnumUpdateSetters)]
pub struct MyState<'a> {
    value: String,
    my_reference: &'a str
}
// `EnumUpdateSetters` will generate:
// impl<'a> MyState<'a> {
//     fn modify_value(&mut self, value: String) -> MyStateUpdate {
//         self.value = value.clone();
//     }
//     fn modify_my_reference(&mut self, my_reference: &'a str) -> MyStateUpdate {
//         self.my_reference = my_reference;
//     }
// }
let mut state: MyState<'static> = MyState {
    value: "hello".to_string(),
    my_reference: "world",
};
state.modify_my_reference("enum updates");
assert_eq!(state, MyState {
    value: "hello".to_string(),
    my_reference: "enum updates"
});

Contributing

Contributions and bug fixes are always welcome. Please open an issue first before implementing a feature or fixing a bug. It is possible that I am already implementing it locally.

Traits

EnumUpdate

Implemented on structs that have their updates represented by some enum U. Implement this trait using the derive macro EnumUpdate.

Derive Macros

EnumUpdate

Generates an enum representing updates to a given struct

EnumUpdateSetters

Generates setter methods that also return enum updates.