I have a repro:

$ osascript -l JavaScript out/main.js '(+ 1 2 3)'
:hello
:args #js [(+ 1 2 3)]
6

(ns 
  (:require [sci.core :as sci]))

(defn ^:export run [args]
  (println :hello)
  (println :args args)
  #_(prn (-> (js/Application "Safari")
           (.-windows)
           (.at 0)
           (.-tabs)
           (.at 0)
           (.url)))
  (sci/eval-string (first args)
                   {:classes {'js goog/global
                              :allow :all}}))

(set! (.-run goog.global) run)

;; shadow-cljs configuration
{:deps true
 :builds
 {:main {:target :browser
         :output-dir "out"
         :modules {:main {:entries []}}
         :compiler-options {:optimizations :simple}}}}

npx shadow-cljs release main

$ osascript -l JavaScript out/main.js '(def x (js/Application "Safari")) (def docs (.-documents x)) (some? docs) '
:hello
:args #js [(def x (js/Application "Safari")) (def docs (.-documents x)) (some? docs) ]
out/main.js: execution error: Error: #error {:message "Can't convert types.", :data {:type :sci/error, :line 1, :column 62, :message "Can't convert types.", :sci.impl/callstack #object[cljs.core.Volatile {:val ({:line 1, :column 62, :ns #object[sci.impl.vars.SciNamespace], :file nil, :sci.impl/f-meta {:ns #object[sci.impl.vars.SciNamespace], :name some?, :sci/built-in true, :arglists ([x]), :doc "Returns true if x is not nil, false otherwise."}})}], :file nil, :locals {}}, :cause #object[Error Error: Can't convert types.]} (-2700)

But I don't understand why it works like this

Weird, right? I’m puzzled too.

Ah, this is more clever than what I was doing:

(set! (.-run goog.global) run)

I'm under the impression that some of the behavior of osascript is "lazy" or so:

var safari = Application("Safari");
var docs = safari["documents"];
console.log(docs);

/tmp/osa.js: execution error: Error: Error: Can't get object. (-1728)

@zane This is kind of what happens in SCI:

var safari = Application("Safari");
var docs = safari["documents"];
var doc = docs[0];
var docurl = doc["url"];
console.log(docurl.apply(doc));

Ah, interesting.

That explains why my attempts to do something similar with aget and so on were unsuccessful.

You might be able to ask the internet why the above doesn't work

I would be curious to learn

I’ll do some digging.

My understanding is still fuzzy, but:

It appears that many of the values in JXA are “Object Specifiers”. They appear to be like “paths” or a “pointers”. They are not like regular JavaScript objects in that when you access a property on one you always get back another object specifier. When you finally call the specifier you get back an actual JavaScript object if the path refers to a value. If the path does not refer to a value you get the error we’ve been seeing.

>> Application("Safari").documents[0] instanceof ObjectSpecifier
=> true

>> Application("Safari").documents[0].foo instanceof ObjectSpecifier
=> true

>> Application("Safari").documents[0].foo.bar.baz instanceof ObjectSpecifier
=> true

>> Application("Safari").documents[0].foo.bar.baz()
!! Error: Error: Can't convert types.

This is true regardless of what you provide as arguments.

>> Application("Safari").documents[0].foo.bar.baz("anything")
!! Error: Error: Can't convert types.

So it would seem that when sci attempts to call a function the .apply returns an object specifier that refers to an invalid location. That object specifier, when called, triggers the error.

right

I’m wondering whether we can work around this by assigning .apply to the object specifier prototype.

hmm, worth a shot :)

Otherwise it may be that sci just isn’t a good fit for JXA, which is a bummer.

If this worked one could create whole MacOS apps powered by sci.

>> Application("Safari").documents[0].url.__proto__["apply"] = Application("Safari").documents[0].url.__proto__["callAsFunction"]
=> [function anonymous] {
  "length":0,
  "name":"",
  "prototype":{"constructor":[function anonymous]}
}
>> Application("Safari").documents[0].url.apply()
=> ""
>> Application("Safari").documents[0].text.apply()
=> "About\nStore\nGmailImages\n\n\n\n  \nAdvertising\nBusiness\nHow Search works\nCarbon neutral since 2007\nPrivacy\nTerms\nSettings\n"

nice hack :)

It’s definitely .apply that sci is using?

you can see the interop code here: https://github.com/babashka/sci/blob/master/src/sci/impl/interop.cljc

try using ["documents"] in your JS code as a closer approximation

Thank you!

or [k] with k = "documents", perhaps they optimize that direct string access to some special accessor or so

Hmm. I think a call other than .apply is triggering this.

@zane Perhaps you can run with a local/root sci and then insert some debugging statements in there

I've tried and added debugging here:

(js/console.log "getting field name" field-name)
             (aget obj field-name)]
      :

$ osascript -l JavaScript out/main.js '(def x (.-documents (js/Application "Safari"))) x'
:hello
:args #js [(def x (.-documents (js/Application "Safari"))) x]
out/main.js: execution error: Error: Error: Can't convert types. (-1700)

no output so perhaps it's happening already with the static field access of the global object

That should work, actually.

I think.

I think the error you’re getting there is triggered when the result is printed.

sorry I was wrong, I needed to restart my shadow server

$ osascript -l JavaScript out/main.js '(def x (js/Application "Safari")) x'
:hello
:args #js [(def x (js/Application "Safari")) x]
invoking method Application
Application("Safari")

$ osascript -l JavaScript out/main.js '(def x (.-documents (js/Application "Safari"))) x'
:hello
:args #js [(def x (.-documents (js/Application "Safari"))) x]
invoking method Application
getting field name documents
out/main.js: execution error: Error: Error: Can't convert types. (-1700)

printing the type of the resulting field value:

$ osascript -l JavaScript out/main.js '(def x (.-documents (js/Application "Safari"))) x'
:hello
:args #js [(def x (.-documents (js/Application "Safari"))) x]
invoking method Application
res function Object() {
    [native code]
}

$ osascript -l JavaScript out/main.js '(def x (.-documents (js/Application "Safari"))) x'
:hello
:args #js [(def x (.-documents (js/Application "Safari"))) x]
invoking method Application
res function Object() {
    [native code]
}
getting field name documents
res function Object() {
    [native code]
}
out/main.js: execution error: Error: Error: Can't convert types. (-1700)

so it seems the interop works ok

but when using the value then something weird happens

We have slightly different test harnesses, I believe.

❯ ./out/obb -e '(.-documents (js/Application "Safari"))'
Application("Safari").documents

That does work. But note:

$ osascript -l JavaScript out/main.js '(def x (.-documents (js/Application "Safari"))) (prn :foo) (def doc (aget x 0)) (prn :dude) (prn (.url doc))'
:hello
:args #js [(def x (.-documents (js/Application "Safari"))) (prn :foo) (def doc (aget x 0)) (prn :dude) (prn (.url doc))]
invoking method Application
res function Object() {
    [native code]
}
getting field name documents
res function Object() {
    [native code]
}
:foo
out/main.js: execution error: Error: #error {:message "Can't convert types.", :data {:type :sci/error, :line 1, :column 69, :message "Can't convert types.", :sci.impl/callstack #object[cljs.core.Volatile {:val ({:line 1, :column 69, :ns #object[sci.impl.vars.SciNamespace], :file nil, :sci.impl/f-meta {:ns #object[sci.impl.vars.SciNamespace], :name aget, :sci/built-in true, :arglists ([array idx] [array idx & idxs]), :doc "Returns the value at the index/indices. Works on JavaScript arrays.", :sci.impl/inlined #object[Function]}})}], :file nil, :locals {}}, :cause #object[Error Error: Can't convert types.]} (-2700)

It still prints :foo. But when you are going to do something with x then it barfs.

Instead of

(set! (.-run goog.global) run)

function run(args) { return namespace.of.run(args); }

That should make (.-documents …) work at least.

That does work. See output above.

Ah, sorry. Missed that.

It's when you are doing something to that documents value, when it barfs.

Right.

:thinking_face:

Wait, this works for me:

(-> (js/Application "Safari")
    (.-documents)
    (aget 0))

❯ ./out/obb -e '(-> (js/Application "Safari") (.-documents) (aget 0))'
Application("Safari").(0)

It’s only this that fails for me now:

❯ ./out/obb -e '(-> (js/Application "Safari") (.-documents) (aget 0) (.url))'
./out/obb: execution error: Error: Error: Can't convert types. (-1700)

$ osascript -l JavaScript out/main.js '(-> (js/Application "Safari") (.-documents) (aget 0))'
:hello
:args #js [(-> (js/Application "Safari") (.-documents) (aget 0))]
invoking method Application
res function Object() {
    [native code]
}
getting field name documents
res function Object() {
    [native code]
}
Application("Safari").(0)

Excellent.

it's as if it builds some lens into the object which is evaluated by need or so

Something like that.

You can deref the “lens” by applying the value. e.g. In the osascript REPL.

>> Application("Safari").documents[0]()
=> Application("Safari").documents.byName("Google")

aha

I think it should be possible to patch Sci to special case instances of js/ObjectSpecifier. I’m just not where to apply the patch yet.

Might be needed in several places.

That could work in a forked sci, special for obb

Or I think obb could just set! the appropriate methods before running.

yeah, if you can get away with it like that, then it would be an easy workaround

Wow, that was harrowing.

what was?

Getting this working.

But I think it’s good now!

oh really? :-D what did you do?

Needs cleaning up, but it should give you the idea.

Key insights are that object specifiers don’t have .apply, and will crash if map? is called on them.

❯ out/obb -e '(-> (js/Application "Safari") (.-documents) (aget 0) (.url))'
favorites://

wow!!

btw I think you're doing one thing too many here:

+             (aget obj field-name)
+             (gobject/get obj field-name)]

either the first or the last can go

Whoops, yeah.

Let me see if it still works if I back out that change.

Still works.

congrats

Thanks!

I think this could be pretty useful to folks.

Do you have thoughts about how it should relate to Babashka? e.g I’d be happy to use a different name if you’d prefer.

btw, I think you might get away with a (set! ...) to replace the existing SCI impl if you don't want to fork.

I'm fine with obb, but perhaps you can come up with a better name, either way I'm fine with it

osciscript?

closa

I'll let it up to you :)

I've also used the patching technique here: https://github.com/oxalorg/4ever-clojure/blob/80963a2e92321e5b8439e87d36c392e740592788/src/app/sci.cljs#L26

That is for preventing the browser to hang. Just be aware you're relying on impl details, but as long as you have tests and compile with a specific version of SCI, it should be fine

Got it.

Sounds good!

If you find there are (performance) improvements to be made in the interop, feel free to provide feedback.

“Is my video enabled on my Zoom call?”

#!/path/to/obb

(-> (js/Application "System Events")
    .-processes
    (.byName "")
    .-menuBars
    (aget 0)
    .-menuBarItems
    (.byName "Meeting")
    .-menus
    (aget 0)
    .-menuItems
    (.byName "Stop Video")
    .exists)

off to bed now. kudos!

Thanks for all the help!

(and for sci)

Sure thing! Perhaps it would make sense to host this under the babashka organization with you as the main admin/maintainer? I would be ok with this. But also fine if you want to host under your personal account.

Just let me know how you want to proceed and I'll set some repo up if necessary

@U04V15CAJ I think that hosting it under the babashka organization sounds great! Let’s keep the “obb” name. I like the symmetry with nbb.

Also, candidly, I don’t have a ton of experience maintaining open-source projects. I’d be grateful any advice or mentorship you’d care to provide.

https://github.com/babashka/obb

Added you as an admin there and sure, I will mentor :)

Great!

I’m ‘zane’ on GitHub, if that wasn’t already clear.

yes, that's the one I added as admin

Seeing that access to stdin/stiout must be provided explicitly (https://github.com/babashka/sci#stdout-and-stdin) I'm inclinded to believe that the default env is pure. But I'd like to be sure :)

Also, are there docs other than the README? (not implying that there should be)

Yes, should be pure/free of mutations to the host unless allowed

README is the main doc

great - thanks! That was what I hoped for.