How to define a complicated hyphenation for Chinese pinyin

Question

I am setting a document with Chinese pinyin. I use \- to separate syllables in pinyin phrases (eg. zhong\-wen). This not only allows for proper hyphenation, but also allows spell check in Emacs/AUCtex. A problem occurs with the hyphen for such words as Chang'an or Xi'an. Entering these words as Chang'\-an or Xi'\-an would retain the apostrophe even if hyphenated at the end of the line. Is there a way to make the apostrophe drop if the word is hyphenated, but kept otherwise?

Answer 1

\- is defined via the \discretionary primitive, so you should be able to go

Xi\discretionary{-}{}{'}an

where the arguments are the text to use before a break, after a break, or if no break.