Originally published on php2rust.dev — part of the PHP to Rust course. View this lesson on the original site.

Enums define a type by listing its variants. Rust enums can hold associated data (like structs per variant), making them more expressive than PHP enums or backed enums.

Rust

enum Color {
    Rgb(u8, u8, u8),
    Named(String),
}

fn describe(c: &Color) {
    match c {
        Color::Rgb(r, g, b) => println!("RGB {}, {}, {}", r, g, b),
        Color::Named(s) => println!("Named: {}", s),
    }
}

fn main() {
    let red = Color::Rgb(255, 0, 0);
    let custom = Color::Named(String::from("Forest Green"));
    describe(&red);
    describe(&custom);
}

PHP

<?php
// PHP 8.1+ backed enum (no associated data per variant)
enum Color: string {
    case Red = 'red';
    case ForestGreen = 'forest green';
}

// For associated data, use classes or unions
$red = Color::Red;
$custom = Color::ForestGreen;
echo $red->value . "\n";

Comparison

Rust: Enum variants can carry different data types (tuples, structs, etc.).
PHP: Backed enums (8.1+) map to scalar values; no arbitrary per-variant data.
Rust: Color::Rgb(255, 0, 0) and Color::Named("...") are the same enum type.
PHP: For variant-specific data, use classes or interfaces instead of enums.

References

What's next

Next: Defining enums.

From PHP to Rust — Rust Syntax and Functions