Re: Confusing typed/racket error message

Taahir Ahmed <[email protected]>
Newsgroups gmane.comp.lang.racket.user,gmane.lisp.scheme.plt
Message-ID <CABpVvxH6cfvMWO=P5MBbrvdCm249S7xS9FbSKdUGOeaKBm1vwg@mail.gmail.com>
Of course it's something simple like that.  You are correct, I changed
it to `#:replacement?` and then the program typechecked and ran.

It would be helpful if the error message showed me that I was passing
extra arguments in the domain of the function, but at least now I know
what was happening.

Thanks!

On Tue, Oct 3, 2017 at 10:29 AM, Shu-Hung You
<[email protected]> wrote:
> Hi Taahir,
>
> The keyword is #:replacement? instead of #:replacement (note the
> question mark). I don't know enough Typed Racket to understand that
> error message tho, sorry.
>
> Cheers,
> Shu-Hung
>
> On Tue, Oct 3, 2017 at 1:40 AM, Taahir Ahmed <[email protected]> wrote:
>> Hi,
>>
>> I have been implementing some toy problems in typed/racket.  However,
>> I have hit a wall while trying to invoke `(random-sample)`.  This
>> example program:
>>
>> ````
>> #lang typed/racket
>>
>> (require typed/racket/random)
>>
>> (define (example (limit : Integer)
>>                  (count : Integer))
>>   : (Listof Integer)
>>   (let* ((random-sample-inst (inst random-sample Integer)))
>>     (random-sample-inst (in-range -10 limit)
>>                         count
>>                         #:replacement #f)))
>>
>> (example 10 5)
>> ````
>>
>> gives the error message:
>>
>> ````
>> ; /home/ahmedtd/project/reinforcement-learning/type-reproducer.rkt:9:4:
>> Type Checker: No function domains matched in function application:
>> ; Types: (Sequenceof Integer) Integer Pseudo-Random-Generator #f * ->
>> (Listof Integer)
>> ;        (Sequenceof Integer) Integer #f * -> (Listof Integer)
>> ; Arguments: (Sequenceof Integer) Integer #f *
>> ; Expected result: (Listof Integer)
>> ;
>> ;   in: (random-sample-inst (in-range -10 limit) count #:replacement #f)
>> ````
>>
>> Maybe I'm missing something obvious, but it seems like the types of
>> the supplied arguments are an exact match for the types of the second
>> candidate domain printed in the error message.
>>
>> Any ideas on how to invoke this function from typed/racket?
>>
>> Thanks,
>>
>> Taahir Ahmed
>>
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