The Zend_Form class is used to aggregate form elements,
display groups, and subforms. It can then perform the following actions
on those items:
Validation, including retrieving error codes and messages
Value aggregation, including populating items and retrieving both filtered and unfiltered values from all items
Iteration over all items, in the order in which they are entered or based on the order hints retrieved from each item
Rendering of the entire form, either via a single decorator that performs custom rendering or by iterating over each item in the form
While forms created with Zend_Form may be complex, probably
the best use case is for simple forms; its best use is for Rapid
Application Development (RAD) and prototyping.
At its most basic, you simply instantiate a form object:
<?php
// Generic form object:
$form = new Zend_Form();
// Custom form object:
$form = new My_Form()
You can optionally pass in a instance of Zend_Config or an array,
which will be used to set object state and potentially create new elements:
<?php
// Passing in configuration options:
$form = new Zend_Form($config);
Zend_Form is iterable, and will iterate over elements,
display groups, and subforms, using the order they were registered and
any order index each may have. This is useful in cases where you wish to
render the elements manually in the appropriate order.
Zend_Form's magic lies in its ability to serve as a factory
for elements and display groups, as well as the ability to render itself
through decorators.