PHP 7.0 Changes

PHP 7.0 is the starting point for many modernisation projects. It introduced scalar parameter declarations, return types, the null-coalescing operator, the spaceship operator, anonymous classes, and the Throwable hierarchy.

Changes Worth Recognising

• Scalar declarations and return types make function contracts visible.
• $value ?? $fallback replaces common isset() ternaries.
• <=> provides a compact comparator for sorting.
• Errors and exceptions both implement Throwable, which matters in top-level error handling.

Representative Code

<?php

function displayName(?string $name): string
{
    return $name ?? 'Guest';
}

echo displayName(null) . PHP_EOL;
echo [3, 1, 2] <=> [3, 1, 4] ? "different\n" : "same\n";

// Prints:
// Guest
// different

Upgrade Review

• Check old error handlers that only catch Exception.
• Review newly added types against real inputs before enabling strict typing broadly.
• Run the test suite under the target runtime; engine changes can reveal assumptions that syntax review misses.

Modern PHP code routinely relies on PHP 7.0 features, but legacy applications may still carry compatibility patterns written for PHP 5.