anchor.diff:  
   (defun valid-password-p (password)
     (and (>= (length password) 6)
  -       (<= (length password) 32)
          (not (find-if-not #'standard-char-p password))))
   
   (defun valid-display-name-p (display-name)
  
positive.code: (defun find-account (account-name)
    (account-view-value "by_account_name" (string-downcase account-name)))
  
  (defun validate-credentials (account-name password &aux (hashed-pass (hash-password password)))
    (account-view-value "by_account_name_password" (list (string-downcase account-name) hashed-pass)))
  
  (defun account-name (account)
    (doc-val account "account_name"))
  
negative.code:     (assert-required "Confirmation" confirmation)
      (assert-validation (valid-email-p account-name) "Invalid email.")
      (assert-validation (not (find-account account-name)) "Account already exists.")
      (assert-validation (valid-password-p password) "Password must be at least 6 characters long and can't contain funky characters.")
      (assert-validation (valid-display-name-p display-name) "Invalid display name. Display name must be between 4 and 32 alphanumeric characters.")
      (assert-validation (not (find-account-by-display-name display-name)) "Display name already in use.")
      (assert-validation (string= password confirmation) "Password confirmation does not match.")))
  
  (defun create-account (account-name display-name password confirmation)
    (multiple-value-bind (validp errors)
        (validate-new-account account-name display-name password confirmation)
      (if validp
          (let ((uuid (get-uuid)))
            (ensure-doc uuid
                        (mkdoc "type" "account"
                               "account_name" account-name
                               "display_name" display-name
                               "password" (hash-password password uuid)
                               "created_at" (get-universal-time))))
          (values nil errors))))
  