class.forms.php

        // If no value was sent, assume an empty list
        elseif ($data && is_array($data) && !isset($data[$this->name]))
            return array();

        return parent::getValue();
    }
}

class FileUploadError extends Exception {}

class FreeTextField extends FormField {
    static $widget = 'FreeTextWidget';

    function getConfigurationOptions() {
        return array(
            'content' => new TextareaField(array(
                'configuration' => array('html' => true, 'size'=>'large'),
                'label'=>__('Content'), 'required'=>true, 'default'=>'',
                'hint'=>__('Free text shown in the form, such as a disclaimer'),
            )),
        );
    }

    function hasData() {
        return false;
    }

    function isBlockLevel() {
        return true;
    }
}

class FreeTextWidget extends Widget {
    function render($options=array()) {
        $config = $this->field->getConfiguration();
        ?><div class=""><?php
        if ($label = $this->field->getLocal('label')) { ?>
            <h3><?php
            echo Format::htmlchars($label);
        ?></h3><?php
        }
        if ($hint = $this->field->getLocal('hint')) { ?>
        <em><?php
            echo Format::htmlchars($hint);
        ?></em><?php
        } ?>
        <div><?php
            echo Format::viewableImages($config['content']); ?></div>
        </div>
        <?php
    }
}

class VisibilityConstraint {

    const HIDDEN =      0x0001;
    const VISIBLE =     0x0002;

    var $initial;
    var $constraint;

    function __construct($constraint, $initial=self::VISIBLE) {
        $this->constraint = $constraint;
        $this->initial = $initial;
    }

    function emitJavascript($field) {
        $func = 'recheck';
        $form = $field->getForm();
?>
    <script type="text/javascript">
      !(function() {
        var <?php echo $func; ?> = function() {
          var target = $('#field<?php echo $field->getWidget()->id; ?>');

<?php   $fields = $this->getAllFields($this->constraint);
        foreach ($fields as $f) {
            $field = $form->getField($f);
            echo sprintf('var %1$s = $("#%1$s");',
                $field->getWidget()->id);
        }
        $expression = $this->compileQ($this->constraint, $form);
?>
          if (<?php echo $expression; ?>)
            target.slideDown('fast', function (){
                $(this).trigger('show');
                });
          else
            target.slideUp('fast', function (){
                $(this).trigger('hide');
                });
        };

<?php   foreach ($fields as $f) {
            $w = $form->getField($f)->getWidget();
?>
        $('#<?php echo $w->id; ?>').on('change', <?php echo $func; ?>);
        $('#field<?php echo $w->id; ?>').on('show hide', <?php
                echo $func; ?>);
<?php   } ?>
      })();
    </script><?php
    }

    /**
     * Determines if the field was visible when the form was submitted
     */
    function isVisible($field) {
        return $this->compileQPhp($this->constraint, $field);
    }

    function compileQPhp(Q $Q, $field) {
        if (!($form = $field->getForm())) {
            return $this->initial == self::VISIBLE;
        }
        $expr = array();
        foreach ($Q->constraints as $c=>$value) {
            if ($value instanceof Q) {
                $expr[] = $this->compileQPhp($value, $field);
            }
            else {
                @list($f, $op) = explode('__', $c, 2);
                $field = $form->getField($f);
                $wval = $field->getClean();
                switch ($op) {
                case 'eq':
                case null:
                    $expr[] = ($wval == $value && $field->isVisible());
                }
            }
        }
        $glue = $Q->isOred()
            ? function($a, $b) { return $a || $b; }
            : function($a, $b) { return $a && $b; };
        $initial = !$Q->isOred();
        $expression = array_reduce($expr, $glue, $initial);
        if ($Q->isNegated)
            $expression = !$expression;
        return $expression;
    }

    function getAllFields(Q $Q, &$fields=array()) {
        foreach ($Q->constraints as $c=>$value) {
            if ($c instanceof Q) {
                $this->getAllFields($c, $fields);
            }
            else {
                list($f, $op) = explode('__', $c, 2);
                $fields[$f] = true;
            }
        }
        return array_keys($fields);
    }

    function compileQ($Q, $form) {
        $expr = array();
        foreach ($Q->constraints as $c=>$value) {
            if ($value instanceof Q) {
                $expr[] = $this->compileQ($value, $form);
            }
            else {
                list($f, $op) = explode('__', $c, 2);
                $widget = $form->getField($f)->getWidget();
                $id = $widget->id;
                switch ($op) {
                case 'eq':
                case null:
                    $expr[] = sprintf('(%s.is(":visible") && %s)',
                            $id,
                            sprintf('%s == %s',
                                sprintf($widget->getJsValueGetter(), $id),
                                JsonDataEncoder::encode($value))
                            );
                }
            }
        }
        $glue = $Q->isOred() ? ' || ' : ' && ';
        $expression = implode($glue, $expr);
        if (count($expr) > 1)
            $expression = '('.$expression.')';
        if ($Q->isNegated)
            $expression = '!'.$expression;
        return $expression;
    }
}

?>