<?php
  /**
   * args() -- assigns various REQUEST vars to global vars
   * 
   * Arguments are a variable number of strings, each of which will be turned
   * into a global variable (e.g. 'foo' => $foo (or $GLOBALS['foo']))
   * Arguments are assumed to be optional, unless they are followed
   * by a ! (e.g. 'foo!' is 'foo' but required (still 'foo' => $foo))
   * If the argument is preceeded with an = (e.g. '=foo' or '=foo!'), then
   * it will not be trim()'ed before the variable is set.
   * Also, you require that a variable be an array with [] (e.g. foo[]),
   * in which case args are not trimmed.
   * You may also pass all of the arguments as a single array.
   *
   * @param array $vars,...  Optional array of vars; can be passed one-by-one
   *
   * @author davidb
   */
  function args() {
    $keys = func_get_args();
    if (count($keys) == 1 && is_array($keys[0])) $keys = $keys[0];

    foreach ($keys as $key) {
      $trim = true;
      $arr  = false;
      $opt  = true;

      if (!preg_match('/^(=)?([^=\[\]!]+)(\[\])?(\!)?$/', $key, $m))
        die("invalid key format in args: $key");

      $key = $m[2];

      ## =
      if ($m[1] || (isSet($m[3]) && $m[3])) $trim = false;

      ## []
      if (isSet($m[3]) && $m[3]) $arr = true;

      ## !
      if (isSet($m[4]) && $m[4]) $opt = false;

      if ($opt)
        $val = (array_key_exists($key, $_REQUEST))
             ? $_REQUEST[$key] : ($arr ? array() : null);
      else {
        if (!array_key_exists($key, $_REQUEST))
          die("Missing required argument for this page: '$key'");
        $val = $_REQUEST[$key];
      }

      if ($arr && !is_array($val))
        die("Array argument {$key}[] is not an array; is: '$val'");

      if (!$arr && is_array($val))
	die("Scalar argument $key is an array");

      if ($trim && !$arr && !is_null($val))
        $val = trim($val);

      $GLOBALS[$key] = $val;
    }
  }
?>