This library uses some tricks to intern values so that two distances are always equal to one another, no matter the distance in time or space.

use Withinboredom\Distance;
use Withinboredom\Distance\Unit;

$meter = Distance::from(Unit::Meters, 1);
$centimeters = Distance::from(Unit::Centimeters, 100);

echo $meter === $centimeters ? 'true' : 'false'
// outputs: true

You can ensure nobody will accidentally confuse inches with centimeters or Nautical Miles with Miles:

function moveForward(Distance $distance) { /* move */ }

moveForward(Distance::from(Unit::Miles, 10));

You can convert between units and even perform operations, like sorting and arithmetic:

$meter = Meters(1);

$meter = $meter->multiply(10)->add(Inches(10)); // get 10 meters and 10 inches

echo Centimeters(10) < $meter ? 'true' : 'false';
// output: true

You cannot serialize/deserialize/clone Distance objects. However, if you use something like Serde, you can still serialize your value objects:

class Robot {
    public function __construct(
        #[Field('height_in_centimeters')]
        #[DistanceAs(Unit::Centimeters)]
        public Distance $height,
    ) {}
}

$serde = new SerdeCommon(handlers: new \Withinboredom\Distance\SerdeExporter());
$serde->serialize(new Robot(Meters(5)), 'json');

The above will be serialized (and deserialized) from:

{
    "height_in_centimeters": 500
}

There are several distance units supported

• Micrometers
• Millimeters
• Centimeters
• Meters
• Kilometers

• Inches
• Feet
• Yards
• Miles
• Furlongs

• Nautical Miles
• Astronomical Units

How far can I go?

The base unit is in micrometers, so on a 64-bit system you can go ~60AU with micrometer accuracy. For reference, Pluto is usually about 40 AU away from the sun.

If you are limited to 32-bit systems, this is not for you. The maximum distance on a 32-bit system is just a couple of meters.

Why does this exist?

I don’t like magic numbers.

How performant is this?

The main overhead is in autoloading and function-call overhead. Thus, if realtime performance is a concern, you might want to stick to magic numbers.

If you wish to create a PR or update the code here:

1. Clone the repo
2. composer install to install test dependencies
3. yarn to install git hooks for formatting
4. Open in favorite IDE.

Per coding styles are followed.