Only English and numbers JIDs REGEXP

Hi
How to disable the registration of a new username that contain non-English characters , numbers and -_. symbols ?
Version: ejabberd 14.07
Config file: ejabberd.yml
OS: Debian 8

This allows to register only

This allows to register only usernames that contain characters from a to z:

acl:
  ascii:
    user_regexp: "^[a-z]*$"

access:
  register:
    ascii: allow
    all: deny

modules:
  mod_register:
    access: register
Syndicate content