Carbon 2.0 Immutable demonstration

example.php

<?php

$mutable = Carbon::now();
$immutable = CarbonImmutable::now();
$modifiedMutable = $mutable->add(1, 'day');
$modifiedImmutable = CarbonImmutable::now()->add(1, 'day');

var_dump($modifiedMutable === $mutable);             // bool(true)
var_dump($mutable->isoFormat('dddd D'));             // string(8) "Sunday 3"
var_dump($modifiedMutable->isoFormat('dddd D'));     // string(8) "Sunday 3"
// So it means $mutable and $modifiedMutable are the same object
// both set to now + 1 day.
var_dump($modifiedImmutable === $immutable);         // bool(false)
var_dump($immutable->isoFormat('dddd D'));           // string(10) "Saturday 2"
var_dump($modifiedImmutable->isoFormat('dddd D'));   // string(8) "Sunday 3"
// While $immutable is still set to now and cannot be changed and
// $modifiedImmutable is a new instance created from $immutable
// set to now + 1 day.

$mutable = CarbonImmutable::now()->toMutable();
var_dump($mutable->isMutable());                     // bool(true)
var_dump($mutable->isImmutable());                   // bool(false)
$immutable = Carbon::now()->toImmutable();
var_dump($immutable->isMutable());                   // bool(false)
var_dump($immutable->isImmutable());                 // bool(true)

Nice one! I think line 6 should be $immutable->add(... though