[ruby-core:23183] String Escapes and Encoding

I'm trying to document the affects of escapes like \x and \u on String  
Encoding, for the m17n series on my blog.  Here are the rules I'm  
aware of:

* A \x String receives the source Encoding if it's not US-ASCII
* A \x String where the escape creates a byte with the 8th bit set is  
upgraded to ASCII-8BIT if the source Encoding is US-ASCII
* A \u String is also given the Encoding of UTF-8

Do I have those rules right?  Are there other escapes that affect the  
String Encoding?

Thanks for the information.

James Edward Gray II