12:21 <TwoNotes> Many library routines return ref objects. Is there a recommended way to convert these to val so they can be sendable?

12:55 <TwoNotes> For example, JsonDoc.data is a JsonType ref. I need to pass a JsonObject val to a constructor.

12:55 <Praetonus> TwoNotes: You can recover to val

12:56 <Praetonus> For example, let myval = recover val myobj.myfun(myarg) end

12:56 <Praetonus> myobj and myarg must be sendable

12:59 <TwoNotes> Not sure how I would create a sendable JsonDoc.

13:00 <Praetonus> Looks like the constructor is iso

13:01 <TwoNotes> But being iso, I can't create aliases to doc.data

13:01 <TwoNotes> I create the JsonDoc, calls its .parse method to give it a JSON string, then I need to pull values out of it

13:02 <Praetonus> I think you can do destructive read: let data = doc.data = None

13:02 <TwoNotes> I start out with a String val of the original JSON data. I need to end up with val versions of the objects described therein

13:02 <Praetonus> Since assignment returns the previous value, I think it works

13:03 <TwoNotes> hmm

13:05 <TwoNotes> So I have to incrementally dismantle the parsed data as I take valuyes out of it.

13:06 <TwoNotes> I am going to therow away the entire JsonDoc at the end of the function... but that doesn't count

13:07 <SeanTAllen> New Gitbook hosted Pony Tutorial is up: http://tutorial.ponylang.org

13:07 <SeanTAllen> You can get Epub, Mobi and PDF versions at https://www.gitbook.com/book/ponylang/pony-tutorial/details

13:08 <Praetonus> By looking at the code of the json package, I don't really understand why data in JsonDoc is ref and not iso. I'll open an issue about it

13:09 <TwoNotes> SeanTAllen, tutorial.ponylang.org says that the tutorial can be accessed at tutorial.ponylang.org.

13:11 <TwoNotes> Praetonus, what I am looking for is a way to go from a String val JSON to val versions of the parsed objects, without having to write 3 pages of code.

13:12 <TwoNotes> The trick is, the intermediate data structures involved in the parsing cannot be val

13:19 <Praetonus> I think the best you can do is to recursively pattern-match on the Json types when you get a JsonArray or a JsonObject

13:20 <Praetonus> What do you want on the other side? An array?

13:20 <doublec> Has something involving AmbientAuth/FilePath changed recently? I updated ponyc and am getting errors in that part of code.

13:21 <Praetonus> doublec: Yes, I've seen something about FilePath in sylvanc's recent overhaul of ambient authority in the net package

13:21 <TwoNotes> I can accomplish this by picking apart the entire JSON structure, then passing simple strings and numbers into the constructors for my final 'val' objects. But that puts knowledge of the JSON/object mapping in my top level code. I want to put that mapping knowledge inside the class constrcturs themselves, and that is where I run into this problem.

13:21 <doublec> Praetonus: thanks, found the commit

13:23 <TwoNotes> Praetonus, starting with a string like {"a":1, "points":[{"x":10,"y":15}, {"x":19,"y":7}]}

13:23 <TwoNotes> I want to construct one object containing 'a' and 'points', and 'points' itself is an Array of xy coordinate objects

13:24 <doublec> I just needed to do an "env.root as AmbientAuth" in places

13:26 <SeanTAllen> yup, that would be it doublec

13:26 <doublec> TwoNotes: can you extract the iso data object from the json and pass that to your class constructors?

13:27 <doublec> TwoNotes: using destructive assignment as suggested by Praetonus

13:29 <TwoNotes> It worked on the topmost element so it would probably work lower down as well. But I think my original way is cleaner. Just do not try to use constructors that take JsonObject as a parameter.

13:30 <Praetonus> SeanTAllen: Did we lost syntax highlighting in the tutorial?

13:37 <doublec> TwoNotes: you can also do the json parsing within a recover, return the result as an iso

13:38 <doublec> TwoNotes: eg http://pastebin.com/YAbMpWLF

13:39 <TwoNotes> Yes, I was thinking of that. I have to parse the entire JSON string into a single toplevel object, with all lower level objects beneath it. And JSON parsng requires the use of 'try' blocks, which constructors do not like

13:40 <TwoNotes> It seems like the 'else' branch of a 'try' is not taken into account when it tests whether all fields have been initialized.

13:42 <doublec> TwoNotes: huh, you're right, it doesn't

13:42 <TwoNotes> I've run into that before... very frustrating

13:42 <TwoNotes> That seems like a bug to me - there is no path thru the code that does not initialize the fields, but the compiler does not see it

13:43 <doublec> Yes, you should raise an issue

13:44 <TwoNotes> There are two ways to use try. a = try 1 else 2 end and the other is try a=1 else a=2 end

13:44 <TwoNotes> I am sure it does not like the second form. Not sure about the first.

13:44 <TwoNotes> But if the thing being try-ed is complex, you really need to use the 2nd form

13:45 <Praetonus> I think there is an open issue about this

13:46 <Praetonus> https://github.com/ponylang/ponyc/issues/664

13:49 <TwoNotes> Yes, that is exactly what I run into. Any time you deal with hash maps, arrays, or parsing, there is a try-block around somewhere

13:50 <TwoNotes> And if you make all your fields unions with None, and initialize them to None, you condemn yourself to having to use a 'match' every time you refer to them.

13:53 <TwoNotes> I added a comment to that issue.

13:59 <doublec> I hit it with TCPConnections. I end up with "conn as TCPConnection" every wrapped in try blocks.

14:00 <doublec> s/every/everywhere/

14:01 <doublec> Or create the connection outside of the actor/class and pass it in the constructor

14:05 <TwoNotes> I don't think creating a TCPConnection can fail. What happens is the Notify callback for failure gets called, and the mainline ends up with a 'conn' variable that won't work. But it still exists

14:05 <TwoNotes> Since a TCPConnection is an actor

14:07 <doublec> TwoNotes: ah right - in my code I use SSL so it's the SSL setup that can fail.

14:50 <SeanTAllen> praetonus: this is needed for syntax highlighting... https://groups.io/g/pony+dev/thread/volunteer_needed_pony/800005?p=,,,20,0,0,0:RecentPostDate,,,20,2,0,800005

20:45 <jeremyheiler> is the process lib code available somewhere?

20:48 <SeanTAllen> jeremyheiler: very soon. Markus is putting together documentation in prep for a PR.

20:49 <jeremyheiler> cool

20:58 <Scramble1ams> Question from my inner language geek: Why is method overloading not supported in Pony?

21:03 <jemc> Scramble1ams: well, pony doesn't really have inheritance, so what are you picturing?

22:26 <TwoNotes> The tutorial has two sections on 'aliasing'; one for types and one for objects. I wonder if that could be confusing. But I do not have any suggestions for a different term to use.

22:27 <TwoNotes> "synonym"