The loop keyword

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

loop creates an infinite loop. Use break to exit and continue to skip to the next iteration. PHP has no direct equivalent; use while (true).

Rust

fn main() {
    let mut counter = 0;
    loop {
        counter += 1;
        println!("Counter: {}", counter);
        if counter == 5 {
            break;
        }
    }
    println!("Done");

    // break can return a value
    let result = loop {
        counter += 1;
        if counter >= 10 {
            break counter * 2;
        }
    };
    println!("Result from break: {}", result);
}

PHP

<?php
$counter = 0;
while (true) {
    $counter++;
    echo "Counter: $counter\n";
    if ($counter === 5) {
        break;
    }
}
echo "Done\n";

Comparison

• Rust: loop is a dedicated construct; break can return a value.
• PHP: while (true) is the usual pattern; break does not return.
• Rust: continue skips to the next iteration.
• PHP: Same behaviour for continue.

References

• Rust: loop
• PHP: while

What's next

Next: The while keyword.

From PHP to Rust — Rust Syntax and Functions