punctuation - Reimplement or re-implement?

Which form is correct (or more correct): reimplement or re-implement?

And to extend the question a little bit, are there any rules concerning both, e.g. re-scan or rescan, re-evaluation or reevaluation?

Edit:

The primary question is if both versions are correct (or which one is more correct from the English grammar's point of view). I know that both are in use, it's easy to do Google search for example to find out that "reimplement" is even more widely used than "re-implement". But in that case, why LibreOffice marks "reimplement" as incorrect? Is the construction informal? Incorrect? Because clearly is quite popular.

The second part of the question is somehow answered by the other question pointed to in the comment, e.g. I may use the hyphen if that makes the meaning more clear (which doesn't apply to this case IMHO).

Answer

Thanks for all the answers, but I found what I was looking for in the Hyphens with the Prefix re article:

Rule: Use the hyphen with the prefix re only when re means again AND omitting the hyphen would cause confusion with another word.

The article then provides some examples (which I am not copying here).

In other words, "reimplement" is the grammatically correct version because there is no other meaning associated with the word "reimplement" and therefore the use of hyphen is not necessary.

This somehow confirms why there is more results in favor of "reimplement" than "re-implement" on Google - the later (less correct, if not incorrect) form is probably a result of the confusion around the usage of hyphen with re.

This is of course based on the assumption that the article is trustful.

Edit: Cater for re-examine

The same page mentions an additional Rule:

Rule 3. For clarity, many writers hyphenate prefixes ending in a vowel
when the root word begins with the same letter.

Example: ultra-ambitious semi-invalid re-elect

http://www.grammarbook.com/punctuation/hyphens.asp