#
# This function redraws the current URI past the ? mark, replacing a given get variable with its new value
#      .... or adding the desired get variable and its value at the end.
#
function munge_uri($variable_to_munge="", $query="") {

  
  if (strlen($query) < 1) {
    global $QUERY_STRING;
    $query = $QUERY_STRING;
  }
  
  if (substr($query, 0, 1) == "?") {
    $query = substr($query, 1, strlen($query)-1);
  }
  
  
  $buf = "";
  
  $vars = split("&", $query);
  
  #print_r($vars);
  
  $middle = strpos($variable_to_munge, "=");
  foreach ($vars as $var) {
  
    if ( substr($var, 0, $middle) == substr($variable_to_munge, 0, $middle) ) {
      # we don't add it here... because if a munged variable doesnt previously exist, we still want to add it at the end.
      
    } else {
      $buf = $buf . $var . "&";
    }
    
  }

    
    #add the replacement variable here... so it will show even if it is new
    $buf = $buf . $variable_to_munge;


  # we need a ?, but we don't want to have ?????? buildup if we call this repeatedly on a string.
  if (substr($buf, 0, 1) != "?") {
    $buf = "?" . $buf;
  }
    
  return $buf;
    
    

}