Add Strict Typing to Inline Variables in PHP With Strictus


June 6th, 2023

Add Strict Typing to Inline Variables in PHP With Strictus

Strictus is a package that brings strict typing to inline variables for PHP. Given the following example, PHP doesn't have a way to enforce strongly-typed inline variables:

// Rule: Active discount of 10% or 25% for orders from $50
$total = 82.50;
$discount = 0.10; // Float
if ($total >= 50) {
$discount = '25%'; // Replacing a float value with string value 🤦🏻‍♂️
$total = $total - ($total * $discount); //💥 Error: A float cannot be multiplied by a string

Using the Strictus class, the above code example now looks like the following:

use Strictus\Strictus;
$total = Strictus::float(82.50);
$discount = Strictus::float(0.10);
if ($total() >= 50) {
$discount(0.25); // Updates the $discount value
$total($total() - ($total() * $discount()));
echo $total(); // 61.875

The above strict example would throw a StrictusTypeException if float() receives anything other than a float type. This might be off-putting if you are used to dynamic variables, but I think you should consider how having stricter variables might help.

At the time of writing, this package supports single types and nullable types for String, Float, Integer, Boolean, Array, Object, Class

use Strictus\Strictus;
Strictus::string($value, true); // nullable
Strictus::nullableString($value); // nullable shortcut
Strictus::int($value, true); // nullable
Strictus::float($value, true); // nullable
// And so on...

You can learn more about this package, get full installation instructions, and view the source code on GitHub.

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Paul Redmond

Full stack web developer. Author of Lumen Programming Guide and Docker for PHP Developers.