Alexander, hello. On 2014 Aug 5, at 14:11, "Alexander D. Knauth" <alexan...@knauth.org> wrote:
> Well ann can’t add any detail, it can only make types less specific. Aha: I was thinking of this the wrong way round. If I type, say, #(1 2) into TR, it determines its type as > #(1 2) - : (Vector Integer Integer) '#(1 2) Compared to that, > (ann #(1 2) (Vectorof Positive-Integer)) - : (Vectorof Positive-Integer) '#(1 2) ...is more specific. But your explanation makes me realise that the most specific possible type is (Vector 1 2) (of limited utility), and that (Vector (U 1 2) (U 1 2), (Vector Integer Integer) and (Vectorof Positive-Integer) are just samples of the many possible less specific ones, and it happens that the less-specific one that TR guesses I want is not the one I actually want. Which is why I have to use `ann`. Simple, really -- cor, it's wall-to-wall epiphanies today.... All the best, Norman -- Norman Gray : http://nxg.me.uk SUPA School of Physics and Astronomy, University of Glasgow, UK ____________________ Racket Users list: http://lists.racket-lang.org/users
