Arcane

Arcane refers to weird and obscure features, that are unknown, unused or forgotten: sometimes, all at the same time. They have been with the language for a long time, and they eventually drop from the feature list.

• It is possible to use ++ on a string containing variables. In that case, trailing letters are augmented by one.

• strpos() used to accept an integer as second argument: it would convert it automatically to its ASCII equivalent

• range() used to produce all the values between the interval boundaries, even when the boundaries where one string and one integer

• Logical operators works on strings, and then, produce strings.

<?php

    $a = 'b';
    echo ++$a; // c

    // 98 is b
    print strpos('abc', 99); // 1
    // This was removed in PHP 8.0

    var_dump(a & 'A' );    // 'A'
    var_dump(a & 'B' );    // '@'

?>

Related : Deprecated, Deprecation