[TYPO3-mvc] FLOW3 Form API backport

[Bernhard Schmitt]

Hi,

I just registered my first FrontendUser using the Form API. There are a 
few things still missing, e.g. the error message output which currently 
doesn't show up. Validation works, though.

Here's what the project currently consists of:
- The FormBackPorter FLOW3 Package
- The backported extension called flow3_form_api (suggestions regarding 
name and key anyone?)
- A prototype FormBuilder extension which does little more than render a 
FlexForm for configuring the settings and render the form itself. The 
Flexform is currently needed for the form selection and the finisher 
configuration (e.g. default user group for the registered user). I can't 
even express how much i like the Signal/Slot pattern :)
- A custom form extension consisting of FormFactories, Finishers, 
Validators and a Slot for feeding the FlexForm.

Currently, I'm facing the following issues:
- Where do the validation error messages go? They don't show up anywhere 
in the form.
- I'll need several markers in the Form API original code to insert 
stuff, e.g. missing child objects.
- In several places, @inject doesn't work. I'll see whether I can get 
past this using the Tx_Extbase_Object_ObjectManager->create() method 
instead of new(). Did you overload new() in FLOW3?
- I'm missing the ButtonViewHelper in Fluid 4.7. I think I'll just 
backport that one along
- Several classes (ConjunctionViewHelper, Utility_Arrays so far) are 
more versatile in FLOW3 than they are in Extbase 4.7. I'll create new 
classes extending the Extbase ones for the Form API
- I'm still not quite sure about the Request/Response stuff. It works so 
far, but I had to comment out some lines (parentRequest for example). I 
also ran into some code that seems to have no functionality in the 
original. But before I go into detail, are there any specific resources 
about the FLOW3 Request/Response concept?

Thanks and best regards
Bernhard

P.S. Since this is very much on the edge between v4MVC and FLOW3, would 
it make sense to post some of this on the FLOW3 list as well?