> On Aug 30, 2016, at 3:22 AM, Jerzy Karczmarczuk > <jerzy.karczmarc...@unicaen.fr> wrote: > > Could anybody justify this convention?
Here the empty set represents the set of all possible result values. That’s a meta-set or a set about things in the language. > An empty set is a legitimate piece of data. If you wanted a function to return the empty set as a piece of data, you would have to choose a set representation. In principle, you ought to be able to construct a singleton type that expresses that a function will return the empty set. — Matthias -- You received this message because you are subscribed to the Google Groups "Racket Users" group. To unsubscribe from this group and stop receiving emails from it, send an email to racket-users+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
