On Mon, Jul 1, 2013 at 2:30 AM, Joseph Wright
<[log in to unmask]> wrote:
> I'm not sure I see the need for this. In the other 'case' functions, at
> most exactly one case can be true
<snip>
> However, in \bool_case:nn you stop at the first case that happens to be
> true. That means that order matters for the result, which isn't what
> happens in the other case functions.

I’ve invited A. Ellett (the fellow who requested \bool_case on TeX.SE)
to join this thread and explain, but my guess would be that he's got a
group of booleans, only one of which is supposed to be set at any
given time: a selection from a set of mutually-exclusive options, for
example.

—Joel