[Haskell-beginners] [OT] To Mock A Mockingbird

Brent Yorgey byorgey at seas.upenn.edu
Wed Sep 8 08:08:37 EDT 2010

On Wed, Sep 08, 2010 at 07:57:14AM -0400, Patrick LeBoutillier wrote:
> Hi all,
> I've been reading the book "To Mock A Mockingbird" by Robert Smullyan
> recently and I don't get the part about the birds at all. I think I
> understand that a bird is a function, but what would it's type be in
> Haskell?
> It says that birds hear a call and answer by another call, so I
> thought String -> String or something like that. But if you have a
> mockingbird that can answer what a bird would answer to itself, that
> means that it's input must contain the other bird... Do all the birds
> have the same type?

No, each bird has its own type; each bird represents some particular
combinator (= polymorphic function).


More information about the Beginners mailing list