Racket already has a built-in JSON parser[0] that works just fine with Arc.

    ($ (require json))
    
    (if
       ((w/instring json "{\"success\":false}"
                          ($.read-json json))
                          'success)
       'success ; proceed to login
       'fail    ; must be a robot then
     )

    arc> (if $.#f 'foo 'bar)
    bar
    arc> (if $.#t 'foo 'bar)
    foo

Also, I don't get why the Anarki repository contains a JSON parser implemented in Racket, when the built-in Racket JSON parser works just fine with Arc:

    arc> ($ (require json))
    arc> ($.write-json (obj foo "bar"))
    {"foo":"bar"}#<void>
    arc> (w/instring in "{\"foo\":\"bar\"}" ($.read-json in))
    #hash((foo . "bar"))

It currently works but that's only because json.rkt has been modified.

    (def post-getjson (url params (o port stdin))
      (fromstring (post-url url params) 
        (read-json (port))))

    (def recaptcha-response (s r)
      (post-getjson "https://www.google.com/recaptcha/api/siteverify"
      (list 'secret s 'response r)))

    (def verify-captcha (req)
      (do
        (= resp (recaptcha-response recaptcha-secret* 
        (alref (req 'args) "g-recaptcha-response")))
      (if resp!success 
        (pr "success") 
        (pr "failure"))))

    arc> (w/instring in "{\"foo\": true}" ($.read-json in))
    #hash((foo . #t))

    #hash((foo . t))

I'd like to see perhaps a specific brief example, where using Racket booleans within Arc actually is a problem, because I haven't encountered any myself.

If I try to use the hash from your example in actual Arc code, it works fine:

    arc> (if ((w/instring in "{\"foo\": true}" ($.read-json in)) 'foo) 'yes 'no)
    yes
    arc> (if ((w/instring in "{\"foo\": false}" ($.read-json in)) 'foo) 'yes 'no)
    no

Ah, here's perhaps the only special-case we need to handle:

    arc> (= x (w/instring in "{\"foo\": null}" ($.read-json in)))
    #hash((foo . null))  # expected: #hash((foo . nil)) or #hash()
    arc> (if x!foo (prn "error"))
    error

Actually the Racket docs[0] clarifies the situation with null in JSON:

    (json-null) → any/c

    (json-null jsnull) → void?
      jsnull : any/c

If you set the JSON null to nil before running your example, it works as you'd expect:

    arc> ($.json-null nil)
    #<void>
    arc> (= x (w/instring in "{\"foo\": null}" ($.read-json in)))
    #hash((foo . nil))
    arc> (if x!foo (prn "error"))
    nil

I recommend (obj), (obj foo (list 'null)), (obj foo (list 'false)), and (obj foo (list (list))). Arc is good at representing optional values as subsingleton lists:

  ; Access a key that's known to be there.
  t!foo.0
  
  ; Access a key that isn't known to be there.
  (iflet (x) t!foo
    (do-something-then x)
    (do-something-else))

Meanwhile, I don't think there's any big deal when we don't have Arc-style booleans....

  ; Branch on the symbols 'false and 'true.
  (if (isnt 'false x)
    (do-something-then)
    (do-something-else))
  
  ; Alternative
  (case x true
    (do-something-then)
    (do-something-else))

We do already have booleans that work in Arc without any conversion. Please see http://arclanguage.org/item?id=20492

But now that I look closer at the ac.scm history (now ac.rkt in Anarki), I realize I was mistaken to believe Arc treated #f as a different value than nil. Turns out Arc has always equated #f and 'nil with `is`, counted them both as falsy, etc. So this library was already returning nil, from Arc's perspective.

There are some things that slip through the cracks. It looks like (type #f) has always given an "unknown type" error, as opposed to returning 'sym as it does for 'nil and '().

Really, #t and #f are not proper Arc booleans[0], so it makes sense that Arc can't tell what type they are.

You can configure the value Arc chooses for a JSON null with the $.json-null function, which I think is fine as JSON APIs might have differing semantics.

There are a lot of ways to conceive of what Arc "is" outside of the Racket implementations, but I think Arc implementations like Rainbow, Jarc, Arcueid, and so on tend to be inspired first by the rather small set of operations showcased in the tutorial and in arc.arc. (As the tutorial says, "The definitions in arc.arc are also an experiment in another way. They are the language spec.") Since #f isn't part of those, it's not something that an Arc implementation would necessarily focus on supporting, so there's a practical sense in which it's not a part of Arc our Arc code can rely on.

Really, #t and #f are not proper Arc anything, but the language apparently handles them so IMHO Arc should also be able to know what type they are. Otherwise, I fear, this will become a Hodge Podge language that will lose appeal.

You don't need to add any $ handlers to handle Racket booleans. They can be passed directly to Arc functions.

  (if #f 'foo 'bar)
 

> The GDPR is applicable to the US entities to the extent such entities process personal data in order to provide a service or a good within the EU territories.

https://www.quora.com/Does-the-GDPR-apply-to-US-companies

> It doesn't matter if you operate or are established in the EU. If you have EU visitors/users they gain the protections of the GDPR and you have to comply.

But the most the EU could do about the Arc forum would be to block EU users from accessing the site (which would be a political nightmare for them in censorship terms). And, in reality, this site doesn't hold any real data worth worrying about and I somehow doubt PG is sitting around worried about what the EU thinks (regarding this site).

    Final-Recipient: rfc822; support@arclanguage.org
    Original-Recipient: rfc822;support@arclanguage.org
    Action: failed
    Status: 5.4.6
    Diagnostic-Code: X-Postfix; mail for arclanguage.org loops back to myself

How would this be different than git submodules?

Most of the difference would be in the user interface. Git submodules might actually be a great idea for how to implement it, to encourage hacking on and submitting changes to the libraries themselves.

Git submodules don't provide a very friendly user experience though. You have to know the repository url and manage them separately. It's not terrible, but it's extra work, and doesn't handle loading the library in your own, or dependency management. Ideally, pulling in a package would also result in pulling in all of its dependencies, without pulling in multiple copies of the same library the way npm used to.