you = weapon;
var dist = c_scan(my.x,my.pan,vector(180,0,1000),scan_ents|ignore_me|ignore_you|ignore_passable);
if(dist!=0)
{ 
   //do something cause "you" is NOW the closest entity, which isnt weapon.
}
if(dist==0)
{
   //do nothing, cause nothing was found and weapon is still in the "you" pointer.
}