[schrodinger]

In my experience the em dash is still correctly used, the modern style has just evolved to put a space around it.

So:

* fragment a—fragment b (em dash, no space) = traditional

* fragment a — fragment B (em dash with spaces) = modern

* fragment a -- fragment b (two hyphens) = acceptable sub when you can’t get a proper em to render

But en-dashes are for numeric ranges…

[lxgr]

em dash plus spaces is quite rare in English style guides. It’s usually either an em dash and no spaces or an en dash with them.

[schrodinger]

Apologies, now that I've been Beider-Meinhoff'd, I've realized you're correct and I've been misreading en dashes and em dashes. Thank you!