dev_notes.txt

HTML::FormHandler
  form object. contains roles to build fields and a Result object
HTML::FormHandler::BuildFields
  Builds the field arrays. Used by HFH & Field::Compound
HTML::FormHandler::InitResult
  Methods to initialize the fields
HTML::FormHandler::Fields
  Attributes and methods for the Field arrays and accessors
  Used by HFH and Field::Compound
HTML::FormHandler::Result
  Result object that contains non-static data: input, value, errors
  mostly implemented by HTML::FormHandler::Result::Role
HTML::FormHandller::Validate
  Role that hold validation code (used in Field)
HTML::FormHandler::Validate::Action
  Role that validates the action array (use in HFH & Field)
HTML::FormHandler::Field::Compound
  Implements compound fields, mostly via the Fields role
HTML::FormHandler::Field::Repeatable
  Implements repeatable fields
HTML::FormHandler::Widget::Field::Result
  Field result object, mostly implemented by HTML::FormHandler::Field::Result 
HTML::FormHandler::Types
  Library of Moose types (not used internally)
HTML::FormHandler::Params
  munges params from CGI style to hashes and arrays
HTML::FormHandler::Widget::ApplyRole
  method to apply widget roles to HFH and Field
HTML::FormHandler::Widget::Form::*
  form widgets
HTML::FormHandler::Widget::Field::*
  field widgets
HTML::FormHandler::Widget::Wrapper::*
  wrapper widgets


Form fields are filled in with input/value by _result_from_object if there's
  an initial object or model object (row), by _result_from_input if
  there are params, and by the '_result_from_fields' if there's neither an
  initial object or params (such as when the form is empty).

There are three methods in InitResult (called by setup_form) to do the
field initialization:
  _result_from_fields
  _result_from_input
  _result_from_object

If there are parameters (i.e. POST) then validation is performed.
validate_form in HFH calls _fields_validate in the Fields role.

Validation
   validate_form (HFH)
      fields_validate (Fields in HFH & Compound)
         loop through fields doing 'validate_field' (TransformAndCheck in HFH & Field)
            fields_validate ( if field is Compound (recursive))
            _apply_actions (T&C)
            validate (Field subclasses)
            _validate (form method pointed to in Field)

The fields contain weak references to the result objects they contain. Each field
result object is chained to a parent result object in the _result_from methods.
Each field contains it's own _result_from methods. The Fields class contains the
methods for form and compound fields. Repeatable contains its own versions of these methods.