Can traits be used on enum types? Yes. In fact, you already have multiple traits defined for your enum; the traits Debug, Copy and Clone: #[derive(Debug, Copy, Clone)] pub enum SceneType The problem is that you aren’t attempting to implement Playable for your enum, you are trying to implement it for one of the enum’s … Read more
First have a look at the free, official Rust book The Rust Programming Language, specifically the chapter on enums. match fn initialize(datastore: DatabaseType) { match datastore { DatabaseType::Memory => { // … } DatabaseType::RocksDB => { // … } } } if let fn initialize(datastore: DatabaseType) { if let DatabaseType::Memory = datastore { // … … Read more
Create an Enum: enum ACTIVE_OPTIONS { HOME = 0, USERS = 1, PLAYERS = 2 } Create a component, be sure your enum list will have the typeof: export class AppComponent { ACTIVE_OPTIONS = ACTIVE_OPTIONS; active: ACTIVE_OPTIONS; } Create a template: <li [ngClass]=”{ ‘active’: active === ACTIVE_OPTIONS.HOME }”> <a routerLink=”/in”> <i class=”fa fa-fw fa-dashboard”></i> Home … Read more
First of all, the argument of fromInt() should be an Int, not an Int?. Trying to get a Type using null will obviously lead to null, and a caller shouldn’t even try doing that. The Map has also no reason to be mutable. The code can be reduced to: companion object { private val map … Read more
Beginning 1.8, you can use enums like this: enum Fruit { apple, banana } main() { var a = Fruit.apple; switch (a) { case Fruit.apple: print(‘it is an apple’); break; } // get all the values of the enums for (List<Fruit> value in Fruit.values) { print(value); } // get the second value print(Fruit.values[1]); } The … Read more
You can use the strum crate to easily iterate through the values of an enum. use strum::IntoEnumIterator; // 0.17.1 use strum_macros::EnumIter; // 0.17.1 #[derive(Debug, EnumIter)] enum Direction { NORTH, SOUTH, EAST, WEST, } fn main() { for direction in Direction::iter() { println!(“{:?}”, direction); } } Output: NORTH SOUTH EAST WEST
It’s not possible to ensure the parameter is an enum, because enumerations in TS don’t inherit from a common ancestor or interface. TypeScript brings static analysis. Your code uses dynamic programming with Object.keys and e[dynamicKey]. For dynamic codes, the type any is convenient. Your code is buggy: length() doesn’t exists, e[Math.floor((Math.random() * length)+1)] returns a … Read more
This is the JavaScript output of that enum: var MyEnum; (function (MyEnum) { MyEnum[MyEnum[“First”] = 0] = “First”; MyEnum[MyEnum[“Second”] = 1] = “Second”; MyEnum[MyEnum[“Third”] = 2] = “Third”; })(MyEnum || (MyEnum = {})); Which is an object like this: { “0”: “First”, “1”: “Second”, “2”: “Third”, “First”: 0, “Second”: 1, “Third”: 2 } Enum Members … Read more
Dart 2.7 comes with new feature called Extension methods. Now you can write your own methods for Enum as simple as that! enum Day { monday, tuesday } extension ParseToString on Day { String toShortString() { return this.toString().split(‘.’).last; } } main() { Day monday = Day.monday; print(monday.toShortString()); //prints ‘monday’ }
Not really. What I have seen is introducing a new struct for each enum variant, and then methods on the enum to decompose it: struct Dog(i32); struct Cat(u8); enum Animal { Dog(Dog), Cat(Cat), } impl Animal { fn cat(self) -> Cat { if let Animal::Cat(c) = self { c } else { panic!(“Not a cat”) … Read more