Online PHP editor | refs for KdkVP

<?php $a = [null]; echo 'null, valid cast: ' . array_product($a) . "\n\n"; $a = [false]; echo 'false, valid cast: ' . array_product($a) . "\n\n"; $a = [true]; echo 'true, valid cast: ' . array_product($a) . "\n\n"; $a = ['']; echo 'empty string, invalid cast: ' . array_product($a) . "\n\n"; $a = ['42.5']; echo 'string of a float, valid cast: ' . array_product($a) . "\n\n"; $a = ['42,5']; echo 'string of comma-separated float, valid cast but not desirable (discards trailing chars): ' . array_product($a) . "\n\n"; $a = ['42a']; echo 'string of int with trailing alpha char, valid cast but not desirable (discards trailing chars): ' . array_product($a) . "\n\n"; $a = ['a42']; echo 'string of int with leading alpha char, invalid cast: ' . array_product($a) . "\n\n"; $a = [[]]; echo 'array, invalid cast: ' . array_product($a) . "\n\n"; $a = [new stdClass()]; echo 'class that does not auto-cast, invalid cast: ' . array_product($a) . "\n\n"; $a = [gmp_init(42)]; echo 'gmp, valid cast: ' . array_product($a) . "\n\n";