{{macro}} has basic aids to auto populate form fields with previously sent data. There are also tags for generating <select> tags with options and for rendering validation errors.

Here is the list of the most commonly used {{macro}} tags that can be helpful while dealing with forms:

• Tag {{form}} - an analog of regular html <form> tag . Acts as a data container for child tags, holds initial or posted data as well as server-side validation errors.
• Tag {{form:errors}} - used to extract validation errors from parent {{form}} tag into a local variable that can be used in {{list}} tag to render validation errors.
• Tag {{input}} - an analog of regular html <input> tag. The functionality of {{input}} tag depends on its «type» attribute.
• Tag {{select}} - an analog of regular html <select> tag. Renders options list and marks selected options. The tag supports both single and multiple selections.

Let's consider a small example in order to demonstrate the following features:

• How to auto populate form fields using {{macro}} form tags
• How to render server-side validation errors
• How to render <select> tag with {{macro}} {{select}} tag
• How to mix {{macro}} form tags and regular html form tags

Suppose we have a template:

{{form name="my_form" method="POST"}}
 
{{form:errors to='$fields_errors'/}}
 
{{list using='$fields_errors'}}
Errors:
<ol class="form_errors">
  {{list:item}}
    <li>{$item.message}</li>
  {{/list:item}}
</ol>
{{/list}}
 
<table>
<tr>
<td>{{label for="title" error_class="error"}}Title{{/label}}</td>
<td>{{input type="text" id="title" name="title" title="Title" error_class="error"/}}</td>
 
<?php $types = array(array('id' => 10, 'name' => 'TypeA'), array('id' => 20, 'name' => 'TypeB')); ?>
 
{{select_options_export from="$types" to="$types_as_options" key_field="id" text_field="name"/}}
 
<td><label for="type">Select type</label></td>
<td>{{select name="type" id="type" title="Type" options="$types_as_options" error_style="style_of_error"/}}</td>
 
<tr>
  <td colspan='2'><input type="submit" value='Run' /></td>
</tr>
</table>
<input type="hidden" name="action" value='create'/>
{{/form}}

We need also a PHP script to run this template:

<?php
set_include_path(dirname(__FILE__) . '/' . PATH_SEPARATOR .
                'path/to/limb/' . PATH_SEPARATOR .
                get_include_path());
 
require_once('limb/macro/common.inc.php');
 
$config = new lmbMacroConfig($cache_dir = dirname(__FILE__ ) . '/cache/',
                             $is_force_compile = false,
                             $is_force_scan = false);
 
$macro = new lmbMacroTemplate('form.phtml', $config);
 
if(count($_POST))
{
  $error_list = array();
  $error_list[] = array('message' => 'Error in {field}', 'fields' => array('field' => 'title'));
  $error_list[] = array('message' => 'Other error in {field}', 'fields' => array('field' => 'type'));
 
  $macro->set('form_my_form_error_list', $error_list); 
  $macro->set('form_my_form_datasource', $_POST); 
}
 
echo $macro->render();
?>

Let's try to run this PHP script under web-server. For the first time you should get the following html:

<form name="my_form" method="POST">
 
<table>
<tr>
<td><label for="title">Title</label></td>
<td><input type="text" id="title" name="title" title="Title" value="" /></td>
 
<td><label for="type">Select type</label></td>
<td><select name="type" id="type" title="Type"><option value="10">TypeA</option><option value="20">TypeB</option></select></td>
 
<tr>
  <td colspan='2'><input type="submit" value='Run' /></td>
</tr>
</table>
<input type="hidden" name="action" value='create'/>
</form>

Now you can try to fill some of the form fields and submit the form. As a result you should get something like this:

<form name="my_form" method="POST">
 
Errors:
<ol class="form_errors">
    <li>Error in Title</li>
    <li>Other error in Type</li>
</ol>
 
<table>
<tr>
<td><label for="title" class="error">Title</label></td>
<td><input type="text" id="title" name="title" title="Title" class="error" value="fds" /></td>
 
<td><label for="type">Select type</label></td>
<td><select name="type" id="type" title="Type" style="style_of_error"><option value="10">TypeA</option><option value="20" selected="true">TypeB</option></select></td>
 
<tr>
  <td colspan='2'><input type="submit" value='Run' /></td>
</tr>
</table>
<input type="hidden" name="action" value='create'/>
</form>

Please note that {{macro}} tag {{label}} rendered an html <label> tag with «error» css-class attribute since there was a validation error for the corresponding form field.( [fields ⇒ array('field' ⇒ 'title')]) and since error_class attribute of {{label}} tag was used. The same feature was used for {{input}} tag.

The next two lines are used to pass data into our {{form}} tag:

  $macro->set('form_my_form_error_list', $error_list); 
  $macro->set('form_my_form_datasource', $_POST); 

• form_xxx_datasource - holds data that {{macro}} form tags can use to auto populate their values.
• form_xxx_error_list - holds server-side validation errors list. Validation errors list is a object of lmbMacroFormErrorList or just a regular array.

xxx - is either id attribute or name attribute of {{form}} tag.

If you use {{macro}} package with VIEW package you should use lmbMacroView :: useForm($form_id), lmbMacroView :: setFormDatasource($datasource, $form_id) to pass data into {{macro}} forms.

It's up to you to use {{macro}} form tags or not. You can always use something like <input type='text' name=«title» value=«{$object.title}»> as a simplest way of fields auto population.