Regex - only allow a space or nothing after a match

David Brabant is close, but I think you actually want to try ending your regular expression with (?!\S) - this will mean you'll match anything not followed by a non-whitespace character. If you just want to match on spaces rather than whitespace, use (?![^ ]).

Use negative look ahead:

(\w+)(\.*)(\(\))+(\s)*(?!.)

The important part for you in the regex above is: (\s)*(?!.)

(\s)* : followed by 0 or more white spaces (?!.) : and no other character