Question

Is it possible to easily convert the string

"4 | 2"

into a standard bitwise comparison so it returns 6.

So that I could accomplish something like this

$var1 = "4 | 2";
if(evalAsBitwise($var1) & 2) {
    return true;
} else {
    return false;
} 

Answer 1

If you split your string with space as the delimiter, you will get three parts: the first number, the operator, and the second number. In your function, you can use switch to determine what operator to use.

Something like

function evalAsBitwise($input) {      

   $parms = explode(" ", $input);       
   $next;
   $op;

   $total = array_shift($parms);

   while (!empty($parms)) {
     $next = array_shift($parms);
     if(is_numeric($next)) {
        switch($op) {
          case "|": $total = $total | intval($next); break;
          case "&": ...
        }
     }
     else {
       $op = $next;
     } 
   }// End while
   return $total;
}

You would also need to test for ~. But it gets more complicated if you need it do more complicated expressions like (a & b ^ (c ^ d)).