arc> (ob (v name "John Doe") (v age 23) (v id 73881))
  (ob (v age 23) (v id 73881) (v name "John Doe"))

  (##ob (v name "John Doe") (v age 23) (v id 73881))

(The v here is for "value." An alternate syntax, (kv ...), could be used for entries where the key isn't quoted.)

(Note that (##ob ...) here is a reader macro call. I'm using a design for reader macros that puts the macro name on the inside of a parenthesis, rather than the approach taken by things like Racket's #hash(...). That way, reader macro names can be descriptive without pushing the indentation far to the right.)

This approach generalizes to just about any other data structure we want, such as graphs, queues, sorted sets, etc. We don't have to pick out new parentheses for each one, and we don't have to specify idiosyncratic indentation rules either, so pretty printing at the REPL can be very nice automatically:

  (ob
    (v name "John Doe")
    (v age 23)
    (v id 73881))
  
  (ob
    (v name
      "John Doe")
    (v age
      23)
    (v id
      73881))

  (ob
   (v name "John Doe")
   (v age 23)
   (v id 73881))
  
  (ob
   (v
    name
    "John Doe")
   (v
    age
    23)
   (v
    id
    73881))

- We may have to represent Arc tables as their own data structure, rather than directly as Racket hashes, so that they print nicely even when they're nested inside other Racket data structures like lists and vectors. This is one distinct place where, for the best possible Racket interop, we may need to avoid representing Arc values the same way as Racket ones. Then again, I think `port-print-handler` might provide the ability to print parts of Racket values using the Arc style, so it could be possible to get very nice interop here.

- In order to get (##foo to be processed as a call to an Arc reader macro called "foo", we would need to replace the Racket ( readtable entry with an entry that behaved the same as it does in non-## cases. Racket's ( syntax isn't as simple as it might seem, as I found out when I wrote a custom open parenthesis for Parendown, and I would be glad to copy out some of my Parendown code to make this work.

- Of course, it would take some design work to decide on Arc-side interfaces for defining things like reader macros, custom write behaviors, and maybe even custom REPL pretty print behaviors and custom quasiquotation behaviors (to determine where unquotes can go). In Racket, customization of the `write` or `print` behavior is usually done in a per-value-type way using `gen:custom-write`, but I think it would be better to associate them with the "current writer" or "current printer" somehow, just as the reader and macroexpander use the "current readtable" and the "current namespace." That would allow us to swap out the writer at the same time as we swap out the reader, rather than letting the `read` and `write` behavior get out of sync. Essentially, I would store all these things in the Arc namespace.

---

Would it be much trouble if I started working toward some of these things for Anarki or Amacx? If I do work on this, which things would need my help the most or would make the best milestones? Honestly, my top priorities right now are Punctaffy and Cene, so even though I can express opinions about Arc, I might not allocate the time to follow through on them myself. (My desire not to burden people with something that I think of as being in only in a half-finished state has always been one of the reasons I commit so rarely to Anarki.)

I know the reader syntax for tables bears very little resemblance to the curly brackets people have been talking about here, and I don't want to trample on that. Maybe tables can `write` with curly brackets while other things tend to use this more general-purpose style.