Originally Posted by pdurrant
hyphen: God the all-terrible
em-dash: ...when there had been enormous casualties on both sides—but before the United States entered the war in 1917.
Apparently, some publishers prefer the use of an en-dash with spaces around " – " instead of an em-dash "—", but it's only a matter of style. I don't say I like that better, but for reflowable text in relatively small screens, I think the en-dash with spaces might lead to better looking text. In the books I've done I use this.
Well... actually I use en-dash with spaces when in the middle of the text, and and em-dash when at the end of a sentece (I've seen books unsing a longer dash, like two em-dashes, in these cases), as in:
"They live as we all should live – undisturbed, indifferent, and without disquiet."
"I beg your pardon. I thought—"