\dash, which is how it's used in most cases, and it's used quite a lot, really doesn't like to line-break before the following word. I agree that line-breaking directly after should be avoided, but there's not the same potential for ambiguity as with a single hyphen, and I think avoiding "overfull \hbox" should be a much greater priority.
\dash{} resolves this, allowing line breaks directly after the spaced em-dash (with the em-dash flush right against the margin, so that's good). Is there a way to get \dash to act the same in both cases? Would a simple \xspace do the trick?
\dash, which is how it's used in most cases, and it's used quite a lot, really doesn't like to line-break before the following word. I agree that line-breaking directly after should be avoided, but there's not the same potential for ambiguity as with a single hyphen, and I think avoiding "overfull \hbox" should be a much greater priority.\dash{}resolves this, allowing line breaks directly after the spaced em-dash (with the em-dash flush right against the margin, so that's good). Is there a way to get \dash to act the same in both cases? Would a simple \xspace do the trick?