<?php
$keywords = "val";
preg_match_all('/\w+(?=;|$)/', $keywords, $matches);
echo implode(' OR ', $matches[0]) . "\n";
$keywords = "val;";
preg_match_all('/\w+(?=;|$)/', $keywords, $matches);
echo implode(' OR ', $matches[0]) . "\n";
$keywords = "val1; val2;";
preg_match_all('/\w+(?=;|$)/', $keywords, $matches);
echo implode(' OR ', $matches[0]) . "\n";
$keywords = "val1; val2";
preg_match_all('/\w+(?=;|$)/', $keywords, $matches);
echo implode(' OR ', $matches[0]) . "\n";
preferences:
25.44 ms | 405 KiB | 5 Q