Hello all,
a short followup on the issue.
I opened a PR[1] and Sam raised an interesting question:
(require (filtered-in
(λ (name)
(and (regexp-match #rx"^unsafe-fx" name)
(regexp-replace #rx"unsafe-" name "")))
racket/unsafe/ops))
ensures that only unsafe-fx... bindings get required as fx... bindings
and no other bindings from racket/unsafe/ops are. However, the following:
(require (filtered-in
(λ (name) (regexp-replace #rx"unsafe-fx" name ""))
racket/unsafe/ops))
does the same trick of not shadowing for example vector-ref with
unsafe-vector-ref - which also solves the problem I encountered and
therefore it might be better suited (as it is a smaller change).
To be honest - both solutions are OK. My personal preference for not
polluting the current namespace with all those unsafe-... bindings is
mostly irrelevant here. Can anyone using racket/unsafe/ops share their
thoughts here?
Also please note that the same applies to flonums and extflonums - which
do not mention the unsafe-... option in the documentation at all. I am
inclined to think that this might be good to fix as well.
Cheers,
Dominik
[1] https://github.com/racket/racket/pull/2975
On 15. 12. 19 11:13, Dominik Pantůček wrote:
> Hi,
>
> On 15. 12. 19 2:57, Jack Firth wrote:
>> I think that documentation fix is a good idea.
>
> I'll submit a PR to appropriate repository later on.
>
>> More broadly, it seems awkward that all of the unsafe ops for
>> different data types are combined together into a single module. I
>> would instead expect there to be modules like racket/fixnum/unsafe,
>> racket/struct/unsafe, racket/vector/unsafe, etc. But I've never used
>> the unsafe ops before, maybe those who have can chime in?
>
> it's not that easy as it is really about the "ops" part. For example if
> you need (make-fxvector ...), you still need to require it using
> (only-in racket/fixnum make-fxvector) as there is no racket/unsafe/ops
> equivalent (which is really NOT surprising).
>
> And also splitting the racket/unsafe/ops into more modules might break a
> thing or two as it has been this way for quite some time. Also it is
> nice - if you are in need of heavy optimizations - to see the list of
> unsafe ops in one place.
>
>
> Cheers,
> Dominik
>
>>
>> On Saturday, December 14, 2019 at 1:03:14 PM UTC-8, Dominik Pantůček
>> wrote:
>>
>> Hello,
>>
>> the documentation at
>> https://docs.racket-lang.org/reference/fixnums.html
>> <https://docs.racket-lang.org/reference/fixnums.html> is misleading
>> at best. If you - as I did - use the suggested approach of requiring
>> optimized (and unsafe) fx... operations from racket/unsafe/ops with:
>>
>> (require (filtered-in (λ (name) (regexp-replace #rx"unsafe-" name
>> "")) racket/unsafe/ops))
>>
>> You end up using _all_ symbols from racket/unsafe/ops. All of them
>> are - of course - uncontracted. Which means that if you issue for
>> example vector-ref on something that is not a vector, it can crash
>> the runtime without any apparent reason - instead of just throwing
>> an exception as one would expect.
>>
>> A simple documentation fix should probably go along the lines:
>>
>> (require racket/require (filtered-in (λ (name) (and (regexp-match
>> #rx"^unsafe-fx" name) (regexp-replace #rx"unsafe-" name "")))
>> racket/unsafe/ops))
>>
>> Or is it just me running into corner cases with optimized Racket
>> code?
>>
>>
>> Cheers, Dominik
>>
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