[racket-dev] syntax-local-inferred-name, keyword functions, and syntax properties

Hi Matthew,

I don't understand why this is the right fix.  In particular, the
keyword application form still uses the inferred name in a way that
doesn't make sense to me.  Can you say more?

Sam

On Sat, Dec 14, 2013 at 11:35 PM, Matthew Flatt <mflatt at cs.utah.edu> wrote:
> I've pushed a repair.
>
> At Mon, 9 Dec 2013 16:56:49 -0500, Sam Tobin-Hochstadt wrote:
>> On Mon, Dec 9, 2013 at 4:50 PM, Robby Findler
>> <robby at eecs.northwestern.edu> wrote:
>> > I'm not really familiar with the way the keyword expansion works. I was just
>> > trying to suggest "obvious" reasons why the code would do such a thing.
>> >
>> > But if you find that changing the name changes the error message, then
>> > changing that would be bad.
>>
>> The point I'm trying to make is that I think the error message is
>> _currently bad_, because there's no reason to think of that procedure
>> as named `foo`. We'd be better off and less confused if the procedure
>> in the error message didn't have a name.
>>
>> If you think changing it would be bad, why do you think the relevant
>> procedure (the one with a keyword named `#:kk`) should be named `foo`?
>>
>> Sam
>>
>> >
>> > Sorry for the noise.
>> >
>> > Robby
>> >
>> >
>> > On Mon, Dec 9, 2013 at 3:41 PM, Sam Tobin-Hochstadt <samth at cs.indiana.edu>
>> > wrote:
>> >>
>> >> Yes, that would work, but I still don't see why that's a useful name to
>> >> use.
>> >>
>> >> Sam
>> >>
>> >> On Mon, Dec 9, 2013 at 4:37 PM, Robby Findler
>> >> <robby at eecs.northwestern.edu> wrote:
>> >> > Would it work to make it use syntax-local-infer-name but only use the
>> >> > symbolic part of that name?
>> >> >
>> >> > Robby
>> >> >
>> >> >
>> >> >
>> >> > On Mon, Dec 9, 2013 at 3:34 PM, Sam Tobin-Hochstadt
>> >> > <samth at cs.indiana.edu>
>> >> > wrote:
>> >> >>
>> >> >> Aha, I found the example:
>> >> >>
>> >> >>    (let ([foo ((lambda (#:kk x) (λ (x) x)) #:k 0)]) (foo 5))
>> >> >>
>> >> >> Has this error:
>> >> >>
>> >> >> application: procedure does not expect an argument with given keyword
>> >> >>   procedure: foo
>> >> >>   given keyword: #:k
>> >> >>   arguments...:
>> >> >>    #:k 0
>> >> >>
>> >> >>
>> >> >> Note that if you make the keywords the same, `foo` is indeed bound to
>> >> >> a procedure, but _not_ to the procedure referred to in the error
>> >> >> message.
>> >> >>
>> >> >> Sam
>> >> >>
>> >> >> On Mon, Dec 9, 2013 at 4:29 PM, Sam Tobin-Hochstadt
>> >> >> <samth at cs.indiana.edu> wrote:
>> >> >> > I haven't found a way to make it happen yet.  But even so, it seems
>> >> >> > like the wrong name.
>> >> >> >
>> >> >> > Sam
>> >> >> >
>> >> >> > On Mon, Dec 9, 2013 at 4:16 PM, Robby Findler
>> >> >> > <robby at eecs.northwestern.edu> wrote:
>> >> >> >> Is it possible that that name can leak out in an error message?
>> >> >> >>
>> >> >> >> Robby
>> >> >> >>
>> >> >> >>
>> >> >> >>
>> >> >> >> On Mon, Dec 9, 2013 at 3:10 PM, Sam Tobin-Hochstadt
>> >> >> >> <samth at cs.indiana.edu>
>> >> >> >> wrote:
>> >> >> >>>
>> >> >> >>> Currently, this program fails with a somewhat bizarre type error:
>> >> >> >>>
>> >> >> >>>     #lang typed/racket
>> >> >> >>>
>> >> >> >>>     (: foo ([#:k Any] -> Integer))
>> >> >> >>>     (define (foo #:k [s #f]) 0)
>> >> >> >>>
>> >> >> >>>     (let: ([i : Integer (foo #:k #t)]) i)
>> >> >> >>>
>> >> >> >>> The reason is that the expansion of keyword applications generates
>> >> >> >>> a
>> >> >> >>> name to use for the function (here `foo`), and it uses
>> >> >> >>> `syntax-local-infer-name` to get the name to use. Unfortunately, in
>> >> >> >>> this case, it produces `i`, an identifier which has an extra syntax
>> >> >> >>> property saying that `i` is an `Integer`.  Of course, `foo` isn't
>> >> >> >>> an
>> >> >> >>> integer, it's a function, and so we get a type error.
>> >> >> >>>
>> >> >> >>> I don't see why the inferred name is the right choice here --
>> >> >> >>> there's
>> >> >> >>> no connection between `i` and the name of the function. I can just
>> >> >> >>> change this to use a fresh name, but I thought I'd ask first.
>> >> >> >>>
>> >> >> >>> Sam
>> >> >> >>> _________________________
>> >> >> >>>   Racket Developers list:
>> >> >> >>>   http://lists.racket-lang.org/dev
>> >> >> >>
>> >> >> >>
>> >> >
>> >> >
>> >
>> >
>>
>> _________________________
>>   Racket Developers list:
>>   http://lists.racket-lang.org/dev