On Tue, Apr 8, 2014 at 2:48 PM, John Clements <[email protected]> wrote: > Here’s a short piece of code that tries to plot an array: > > #lang typed/racket > > (require plot > math/array) > > (define fft-maxes (array #[3.2 978.9 -2397])) > > (: with-indexes (Vectorof (Vector Nonnegative-Integer Real))) > (define with-indexes > (for/vector : (Vectorof (Vector Nonnegative-Integer Real)) > ([i : Nonnegative-Integer (in-naturals)] > [a (in-array fft-maxes)]) > (ann (vector (ann i Nonnegative-Integer) a) > (Vector Nonnegative-Integer Real)))) > > > (plot (lines (in-vector with-indexes))) > > I have two questions. > 1) Is there an easier way to pair an array with indices? This was kind of > challenging.
Try `in-indexed`. > 2) When I run this, I get > > Type Checker: missing type for identifier; > consider using `require/typed' to import it > identifier: idX9 > from module: plot in: #%module-begin > . Type Checker: missing type for identifier; > consider using `require/typed' to import it > identifier: idX54 > from module: plot/no-gui in: #%module-begin > . Type Checker: Summary: 2 errors encountered in: > #%module-begin > #%module-begin These are both from the use of `in-array` and/or `fft-maxes`, not from your for loop. Probably the right thing is to use `plot/typed`. Sam ____________________ Racket Users list: http://lists.racket-lang.org/users
