Forum OpenACS Development: validating filenames

Is template::data::validate::filename intended to be used to validate only the initial part of a filename and not the file extension? Because the regexp in this proc does not include the "." character. So I found that I cannot use -datatype filename in creating a file upload widget to automatically validate filenames submitted from users. Is this intended? Should I be using a different -datatype tag to validate filenames in a file widget?

thanks for tips on how the old hands validate file uploads...