Originally Posted by HarryT
It is indeed very easy. The problem, however, is that if you create books with the standard settings of BookDesigner, the emdashes (or the equivalent "--" of a PG book) get converted not to " - ", but to "-" (without any spaces) and hence can't be distinguished from hyphens. One can of course search for "-" and decide in each individual case whether it should be a hyphen or a dash, but it's a lot of work for a long book. I speak from experience, having done exactly that for a number of books where dashes were missing from the original.
This seems to me to be an obvious bug in BD. Why has it not been fixed? Is BD closed source so it is impossible for people to fix it? I am a bit surprised that BD which seems to have a lot of problems is still used so much and that there is no better alternatives available.
So I assume you don't have space before and after an emdash or an --. Maybe english do not use hyphens so much so you can have a word list for common hyphenated words.