18:18 <plietar> Hi, Why does the #read only include ref, val and box ?

18:18 <plietar> Shouldn't it also include iso and trn ?

18:44 <SeanTAllen> iso isnt readable, it has to be consumed before it can be shared. ditto for trn plietar

18:45 <plietar> SeanTAllen: So are iso^ and trn^ in #read then ?

18:46 <SeanTAllen> ive never tried to verify what happens in the implementation

18:46 <SeanTAllen> if you are trying to send an iso or trn to something that requires a #read, there's probably a better way to do it

18:46 <SeanTAllen> do you have a specific problem you are trying to solve?

18:47 <plietar> Not trying to do anything specific, just getting my head around generics

18:47 <SeanTAllen> so iso^

18:47 <SeanTAllen> that destroys an alias

18:48 <SeanTAllen> iso! is an alias to an iso, which if you hit that as an error , you are probably not doing what you intended

18:48 <SeanTAllen> ditto for trn

18:48 <SeanTAllen> if you see

18:48 <SeanTAllen> iso^ in a generic implementation it means

18:49 <SeanTAllen> "this returned item is an iso, but consume the alias to it so it can be assigned to an iso or any other ref type"

18:49 <SeanTAllen> have you read: https://bluishcoder.co.nz/2016/05/04/bang-hat-and-arrow-in-pony.html plietar ?

18:50 <plietar> Ok that make more sense

18:51 <plietar> Yeah I've seen that

18:51 <plietar> Thanks

18:52 <plietar> For context, I'm an undergrad at Imperial. As a final year project I'm working with Sophia Drossopoulou on extending the model from "Deny Capabilities for Safe, Fast Actors" to describe generics

18:52 <plietar> And show that they preserve soundness

18:52 <SeanTAllen> Ah, Sylvan mentioned that to me the other day

19:08 <plietar> So how would you make a `Map[Foo trn, U8]` for example ?

19:08 <plietar> This doesn't work, but I don't see how it would break soundness

19:10 <plietar> When the map needs to read from the Foo, it can alias it to a Foo box

19:23 <SeanTAllen> you cant alias a trn or iso

19:23 <SeanTAllen> they dont alias to themselves

19:23 <SeanTAllen> that is the problem there

19:24 <SeanTAllen> Map[Foo trn, U8], I'm not sure how based on the definition of `trn` you could create that

19:25 <SeanTAllen> I'm also not sure why would want to make a `Map[Foo trn, U8]`

19:30 <SeanTAllen> I'm assuming that the map comparison is a HashIs, so identity

19:31 <SeanTAllen> So a trn cant be aliased which would mean, you can put it in but you can never get anything out

19:32 <SeanTAllen> from an undergrad project i understand what you are asking but I'm having a hard time imaging how you could use iso, trn in that context (thus the #read)

22:45 <cquinn> what is the default capability of items in an array literal?

22:45 <cquinn> I have a function that expects a `flags': Array[FlagSpec box] box`

22:46 <cquinn> but the literal array I pass like so:

22:46 <cquinn> https://www.irccloud.com/pastebin/5zCjhjT6/

22:47 <cquinn> or maybe the problem is my constructors?

22:53 <cquinn> yup, it was my constructors.

23:19 <SeanTAllen> ha. glad you got it cquinn

23:19 <cquinn> It was one of those funny problems that was obvious once I tried to pose it as a question