Operator overloading extension for PHP7

Usage

Implement magic methods in a class to provide operator overloading automatically, for example:

class C {
  private $value = 0;
  public function __add($delta) {
    $this->value += $delta;
    return $this;
  }

  public function __toString() {
    return strval($this->value);
  }
}

$c = new C;
var_dump($c + 5); // object(C)#1 { ["C:value:private"]=>5 }

The following overload methods are supported:

Operator	Method
$o + $arg	__add($arg)
$o - $arg	__sub($arg)
$o * $arg	__mul($arg)
$o / $arg	__div($arg)
$o % $arg	__mod($arg)
$o ** $arg	__pow($arg)
$o << $arg	__sl($arg)
$o >> $arg	__sr($arg)
$o . $arg	__concat($arg)
$o | $arg	__bw_or($arg)
$o & $arg	__bw_and($arg)
$o ^ $arg	__bw_xor($arg)
~$o	__bw_not()
$o === $arg	__is_identical($arg)
$o !== $arg	__is_not_identical($arg)
$o == $arg	__is_equal($arg)
$o != $arg	__is_not_equal($arg)
$o < $arg	__is_smaller($arg)
$o <= $arg	__is_smaller_or_equal($arg)
$o > $arg	__is_greater($arg) *
$o >= $arg	__is_greater_or_equal($arg) *
$o <=> $arg	__cmp($arg)
++$o	__pre_inc()
$o++	__post_inc()
--$o	__pre_dec()
$o--	__post_dec()
$o = $arg	__assign($arg)
$o += $arg	__assign_add($arg)
$o -= $arg	__assign_sub($arg)
$o *= $arg	__assign_mul($arg)
$o /= $arg	__assign_div($arg)
$o %= $arg	__assign_mod($arg)
$o **= $arg	__assign_pow($arg)
$o <<= $arg	__assign_sl($arg)
$o >>= $arg	__assign_sr($arg)
$o .= $arg	__assign_concat($arg)
$o |= $arg	__assign_bw_or($arg)
$o &= $arg	__assign_bw_and($arg)
$o ^= $arg	__assign_bw_xor($arg)

* - __is_greater() and __is_greater_or_equal() require a rebuild of the main PHP runtime using the included patch. Withtout this patch, $a > $b is automatically remapped to $b < $a by the engine.