Closures & Arrow Functions

Anonymous Functions (Closures)

\$greet = function(string \$name): string {
    return "Hello \$name";
};
echo \$greet("Alice");

// Inherit variables with use
\$prefix = "Mr.";
\$greet = function(\$name) use (\$prefix): string {
    return "Hello \$prefix \$name";
};

Arrow Functions (PHP 7.4+)

\$numbers = [1, 2, 3, 4];
\$doubled = array_map(
    fn(\$n) => \$n * 2,
    \$numbers
);

// Arrow functions automatically inherit parent scope

Callable Type

function process(array \$items, callable \$callback): array {
    return array_map(\$callback, \$items);
}