Spacing around "—"

[devurandom]

The spacing around "—" is often badly typeset. There are also several instances with additional spacing and a prolonged dash in inline code sections that should not be there. I.e. some --name or even some ---name instead of some-name (-- denoting the en dash, --- is again the em dash). Note the additional spacing in front of the dash as well as its prolonged nature (opposed to the intended short "-" minus).

Sometimes this just looks weird, but sometimes it is outright confusing (for example in the explanation of mapify in chapter 4 "Core Functions in Depth").