Let me explain: HTML..FormFu does a lot of dirty job and give you an easy way to write down forms with a lot of business logic, but when you try to open is source code to do some customization it's quite a labyrinth with too much trolls and few indications about the right road.
In my opinion the module could be ten times more powerful giving an easy way to hack elements and modify them for new purposes.
The category selector, probably the most complex widget I had to use, in forms configuration files is something like this:
Problem is that Strehler should give other developers the opportunity to implement their own entities and forms managing them. These forms could contain my category selector and I can't ask people to copy and paste all this code in their YML files. It's really clumsy and what if I change this structure? I should call them one by one and ask to change their files.
- type: Select
message: 'Category needed'
- type: Select
TIdy implementation wants that, when you need a category selector, you just add in your form configuration:
- type: "+Strehler::FormFu::Element::Category"
An ad hoc HTML::FormFu element.
There's not a real path to implement something like that, best way I found is to hack a HTML::FormFu::Element::Block nailing in it a fixed configuration with the elements of my category selector. The result is here.
You can do a lot of thngs exploiting the after BUILD of the HTML::FormFu::Element sub-classes, but you'll be always limited to the possibilities given by the class and its methods and, for example, you'll not have any chance to add custom configuration entries. So this pattern can be useful when you just want to make a package of some existing configurations, but nothing more.
Strehler::FormFu::Element::EntitySelect is something a bit more smart, as you can see here, but it's still an hack on Select I did after giving up on creating a FormFu::Element completely by myself.
Working on that, I drew a class diagram of HTML::FormFu (still 0.9 version), doing a bit of reverse engeneering on it. Here it is, as a gift from me.