Control Flow

if uses PHP boolean conversion. Guard clauses validate early and keep the main path shallow. Traditional switch uses loose comparison and can fall through; PHP 8 match is strict, returns a value, and never falls through.

Practical example

<?php
function grade(int $score): string {
  if ($score < 0 || $score > 100) throw new InvalidArgumentException();
  return match (true) { $score >= 80 => 'excellent', $score >= 50 => 'pass', default => 'retry' };
}

A match without a suitable arm/default throws. Avoid relying on surprising truthiness such as string '0'; transform boundary data into explicit domain types before decision logic.