On Sun, Apr 20, 2014 at 10:39 AM, Alexander D. Knauth <alexan...@knauth.org> wrote: > I’m trying to make a multiplication function that can take either all > numbers or all numbers and one vector, and have it not matter what order > they come in. To do this, I’m using match with list-no-order: > #lang typed/racket > > (require plot/typed/utils) > > (define listof-number? > (make-predicate (Listof Number))) > > (: my* (case-> > (-> One) > (Number Number * -> Number) > ((Vectorof Real) Real * -> (Vectorof Real)) > (Real (Vectorof Real) Real * -> (Vectorof Real)) > (Real Real (Vectorof Real) Real * -> (Vectorof Real)) > (Real Real Real (Vectorof Real) Real * -> (Vectorof Real)) > (Real Real Real Real (Vectorof Real) Real * -> (Vectorof Real)))) > ; if I could, I would do this: > ; (Real * (Vectorof Real) Real * -> (Vectorof Real)) > > (define my* > (case-lambda > [() 1] > [args (match args > [(list-no-order (? vector? v) (? real? ns) ...) > (v* v (apply * ns))] > [(? listof-number? ns) > (apply * ns)])])) > > It’s giving me these errors: > . Type Checker: Expected One, but got Number in: (apply * ns) ; why is it > expecting One there? This looks like a bug. > . Type Checker: Expected (Vectorof Real), but got Any in: v ; the type > shouldn’t be Any, it should at least > ; be VectorTop, > and with the type annotation > ; for my* should > tell it that all of the > ; vectors are > (Vectorof Real), right? That is assuming a simple expansion in match (that TR can follow) which isn't a valid assumption. > . Type Checker: Bad arguments to function in apply: ; shouldn’t it be able > to tell that ns is a > Domains: Number * ; (Listof Number), > especially since > Arguments: (Listof Any) * ; listof-number? was > defined with > in: (apply * ns) ; make-predicate? > . Type Checker: Expected One, but got (Vectorof Real) in: (v* v (apply * > ns)) ; why is it expecting One? Same bug as above. > . Type Checker: Expected Number, but got (Vectorof Real) in: (v* v (apply * > ns)) ;why is it expecting Number? Because it is typechecking the case where there are no vectors and doesn't know that this branch is dead code. > . Type Checker: Expected (Vectorof Real), but got Number in: (apply * > ns);whyis it expecting (Vectorof Real)? Reverse of the above. > > > > ____________________ > Racket Users list: > http://lists.racket-lang.org/users >
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