Local Scope

Variables created inside a function stay local to that function call.

local_scope.php

<?php
function addBonus(int $base): int {
    $bonus = 3;
    $inside = $base + $bonus;
    return $inside;
}

$base = ;
$result = addBonus($base);
$outside = $base;

echo "base=" . $base . "\n";
echo "result=" . $result . "\n";
echo "outside=" . $outside . "\n";

<?php
function addBonus(int $base): int {
    $bonus = 3;
    $inside = $base + $bonus;
    return $inside;
}

$base = ;
$result = addBonus($base);
$outside = $base;

echo "base=" . $base . "\n";
echo "result=" . $result . "\n";
echo "outside=" . $outside . "\n";

<?php
function addBonus(int $base): int {
    $bonus = 3;
    $inside = $base + $bonus;
    return $inside;
}

$base = ;
$result = addBonus($base);
$outside = $base;

echo "base=" . $base . "\n";
echo "result=" . $result . "\n";
echo "outside=" . $outside . "\n";

local variable A local variable belongs to the function call where it is created.