In a double-quoted string, you will have to escape parens, double-quotes and single-quotes by prepending a single-quote.

You would have to escape double-quotes, though.

I like how Smalltalk handles this by allowing both single- and double-quotes as string delimiters:

"This is a string which includes two 'single quote' characters, which aren't escaped"

'This is a string which includes two "double quote" characters, which aren't escaped either'

This wouldn't work for Arc, though, if you also want to be able to use a _single_ single-quote for quoting symbols.

    (map [coerce _ 'int] "foo")
    => '(102 111 111)

    <?php
    require_once('liball.php');
    
    if ($foo = $_POST['foo']) {
      $_SESSION['foo'] = $foo;
      localredirect('b.html');
    }
    sendpage('a');
    ?>

Assuming page c needs to be protected against people just coming to it:

    <?php
    require_once('liball.php');
    if (!($foo = $_SESSION['foo'])) {
      localredirect('a.php');
    }
    sset('foo', $foo);
      
    
    sendpage('c');
    ?>

    you said: {$foo}

    <?php
    // unvarying HTML elided above
    if ($foo = $_POST['foo']) {
      $_SESSION['foo'] = $foo;
      print '<a href="">click here</a>';
    } else if ($foo = $_SESSION['foo']) {
      print 'you said: ' . $foo;
    } else {
      print "<form method='post'><input type='text' name='foo'><input type='submit'></form>";
    }
    ?>

    <?php
      $step = isset ($_POST['step']) ? $_POST['step'] : 0;
      if ($step == 0)
        $_POST = array();

      $_POST['step'] = ($step + 1) % 3;
      echo '<form method="post">';
      foreach ($_POST as $k => $v)
        echo '<input type="hidden" name="' . htmlspecialchars ($k) . '"
            value="' . htmlspecialchars (stripslashes ($v)) . '" />';
    
      echo '<p>';
      switch ($step)
        {
        case 0:
          echo '<input type="text" name="simon-sez">';
          break;
        case 1:
          echo 'Simon sez...';
          break;
        case 2:
          echo htmlspecialchars (stripslashes ($_POST['simon-sez']));
          break;
        }
      echo '</p>';
      echo '<input type="submit" value="Go on" />';
      echo '</form>';
    ?>

    (def myfn ()
      ...)