So I read the snippet, thought 'Yeah, a character class of space, -, ~' and fell on my face in the next couple of lines.
Yeah, I should've known better, I know how to read it. If .. I invest the time and don't glance over a construct and hope to just get it instantly.
I wouldn't want to see this in a code base without proper documentation (be it a comment, a function name or whatever. Something).