yuwuhsien/laravel-bcmath-cast

Laravel BCMath Cast

Laravel Eloquent casts for PHP 8.4's BCMath\Number object API, enabling natural operator-based arithmetic on model attributes while maintaining arbitrary precision decimal accuracy.

Why This Package?

PHP 8.4 introduced the BCMath\Number class with operator overloading, transforming cumbersome decimal calculations:

// Old way with BCMath functions
$total = bcadd(bcmul($price, $quantity), $tax, 2);

// New way with BCMath\Number
$total = ($price * $quantity) + $tax;

This package bridges Laravel's Eloquent ORM with PHP 8.4's BCMath\Number, letting you write clean, precise arithmetic directly on model attributes.

Read more: BCMath Object API in PHP 8.4

Requirements

• PHP 8.4+ (for BCMath\Number class)
• Laravel 12+

Installation

composer require yuwuhsien/laravel-bcmath-cast

Usage

Basic Usage

Add the AsDecimal cast to your Eloquent model:

use YuWuHsien\Decimal\Casts\AsDecimal;

class Product extends Model
{
    protected function casts(): array
    {
        return [
            'price' => AsDecimal::class,
            'cost' => AsDecimal::class,
            'tax_rate' => AsDecimal::class,
        ];
    }
}

Now your model attributes are automatically converted to BCMath\Number objects:

$product = Product::create([
    'price' => '19.99',
    'cost' => '12.50',
    'tax_rate' => '0.0825',
]);

// Attributes are BCMath\Number instances
$product->price instanceof Number; // true

// Perform precise calculations with natural operators
$margin = $product->price - $product->cost; // Number('7.49')
$marginPercent = ($margin / $product->cost) * new Number('100'); // Number('59.92')

// Calculate total with tax
$total = $product->price * (new Number('1') + $product->tax_rate); // Number('21.639175')

Setting Values

The cast accepts multiple input types:

// BCMath\Number objects
$product->price = new Number('29.99');

// Numeric strings (recommended for precision)
$product->price = '29.99';

// Integers
$product->price = 30;

// Floats (works but may lose precision - triggers warning)
$product->price = 29.99; // ⚠️ Warning: precision loss possible

Database Column Types

Use DECIMAL columns, NOT FLOAT:

Schema::create('products', function (Blueprint $table) {
    $table->decimal('price', 10, 2);       // ✅ Correct
    $table->decimal('cost', 10, 4);        // ✅ Correct
    $table->float('amount');               // ❌ Wrong - loses precision
});

The DECIMAL type preserves exact decimal values. Floats introduce rounding errors that defeat the purpose of BCMath.

Testing

# Run tests
composer test

# Run tests with coverage
composer test-coverage

# Run static analysis
composer analyse

License

The MIT License (MIT). Please see License File for more information.