#define xorSwap
////////////////////////////////////////////////////////////////
// xorSwap by Leif902
// This script is a GML implementation of
// the famouse Xor Swapping Algorithm
// and was written for GML by Leif902
// for Wikipedia.
// It has been released into the Public Domain by the author.
// This means you may use it however you wish.
//
// Arguments:
//  argument0 - The name of the first variable
//              as a string.
//  argument1 - The name of the second variable
//              as a string.
//  argument2 - Set to one if both variables are global.
//              If they are both local, leave off.
////////////////////////////////////////////////////////////////

var a, b;
a = string(argument0);
b = string(argument1);

if (!argument2)
{
     if (!variable_local_exists(a) || !variable_local_exists(b))
     {
          show_error('Error: Variable is not defined.',0);
     }
     if (variable_local_get(a) != variable_local_get(b))
     {
          // if a does not already equal b
          // a = a ^ b;
          // b = b ^ a;
          // a = a ^ b;
          variable_local_set(a,variable_local_get(a) ^ variable_local_get(b));
          variable_local_set(b,variable_local_get(b) ^ variable_local_get(a));
          variable_local_set(a,variable_local_get(a) ^ variable_local_get(b));
     }
}
else
{
     if (!variable_global_exists(a) || !variable_global_exists(b))
     {
          show_error('Error: Variable is not defined.',0);
     }
     if (variable_global_get(a) != variable_global_get(b))
     {
          variable_global_set(a,variable_global_get(a) ^ variable_global_get(b));
          variable_global_set(b,variable_global_get(b) ^ variable_global_get(a));
          variable_global_set(a,variable_global_get(a) ^ variable_global_get(b));
     }
}