Creating a generic form element generator

It's pretty easy to create a function that simply outputs a form input tag such as <input type="text" name="whatever" >. In order to make a form generator generically useful, however, we need to think about the bigger picture. Here are some other considerations over and above the basic input tag:

• The form input tag and its associated HTML attributes
• A label that tells the user what information they are entering
• The ability to display entry errors following validation (more on that later!)
• Some sort of wrapper, such as a <div> tag, or an HTML table <td> tag

How to do it...

1. First, we define a Application\Form\Generic class. This will also later serve as a base class for specialized form elements:

   namespace Application\Form;
   
   class Generic
   {
     // some code ...
   }

2. Next, we define some class constants, which will be generally useful in form element generation.
3. The first three will become keys associated with the major...