anchor.diff:  (defun make-form (form-class &optional binding-alist)
     (let ((def (find-form-def form-class))
           (form (make-hash-table :test #'eq)))
  -    (when binding-alist
  -      (bind-form def form binding-alist))
  +    (bind-form def form binding-alist)
       form))
   
   (defun field-raw-value (form field-name)
  
positive.code:            :check-field
             :make-form
             :form-valid-p
             :field-raw-value
             :field-value
             :field-error
             :field-error-format-string
             :form-errors))
  
  (defvar *form-definitions* (make-hash-table :test #'eq))
  (defun ensure-form (name field-definitions)
  
negative.code:   (cadr (gethash field-name form)))
  (defun form-valid-p (form)
    (values (gethash *validp* form)))
  (defun field-error (form field-name)
    (caddr (gethash field-name form)))
  (defun form-errors (form &aux errors)
    (maphash (lambda (field-name field-values)
               (unless (eq *validp* field-name)
                 (when-let (error-string (caddr field-values))
                   (push (cons field-name error-string) errors))))
             form)
    (nreverse errors))
  