I wouldn't want to see any of these added to the base language, but I think it's great that the anarki/git allows the user to create these, and I hope that feature makes it into the official language. Lisp is for creating domain-specific languages, and Arc is supposed to be a compact Lisp, so domain-specific syntax seems like a good thing to me.
I'm also biased, because I want to create my own syntax for a message-passing Arc to be used as the object scripting language for a multi-user VR system. (I haven't even started working on a server for it yet -- just the client and the protocol.) So something like:
capital L means left-associative, so foo/bar/nitz is grouped {{foo / bar} / nitz}.
As an aside, why not <- ? Basically parent<-owner<-id means "send 'id to the result of sending 'owner to parent".
For that matter if an object, such as parent above, is something of very specific type, you can even use the Anarki 'defcall syntax. For example if messageable objects are of type 'messageable, you can do:
I considered <- (along with a lot of other things), but rejected it because the left-associativity of it seemed counter-intuitive, it didn't stand out as much as slashes, and I want it to stand out because it's inconsistent with symbol syntax, it's confusing with -> which conventionally means type-conversion (and which doesn't break up symbols), and it's three times as much effort to type as /.
Slashes are fairly common in symbols, but not at the beginning (except for / itself), so it's unambiguously parseable, though maybe it won't work with this system, now that I think about it. I don't see how to prevent embedded slashes from meaning anything special without the first slash. I.e., I want foo/bar/nitz to be one symbol, but /foo/bar/nitz to be a symbol and two msg calls. Maybe that's too hairy, but I'd hate to break things like w/uniq.
I guess the general solution to any syntax that is confusing to people is a good syntax-highlighting editor.
Well, for that matter having (foo msg) mean "send msg to foo" would be much shorter, and also shows that Scheme was originally a synchronous message-passing language anyway.
