I would just like to point out that this is only possible (as a library) because ar is so damn hackable. Big thanks to aw for making ar.
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I'd also like to note something here. Because you can create custom namespaces, there is the theoretical ability to create a "safe namespace" that would not be able to access things like "system" or similar destructive things.
Then, if you ever wanted to load up a library, rather than inspecting it to make sure it doesn't do anything bad, you could just load it into the safe namespace. This won't protect against things like infinite loops, or programs designed to consume a lot of CPU/RAM, but it will protect against the obvious stuff like (system "rm -rf /") and such.
I haven't added in support for that just yet, but it is planned.
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Also, __built-ins* is a terrible name, and I plan to change it. :P
Yes. And it'll be even more true when ar gets defcall. I mean, really, implementing dynamic variables, optional args/destructuring, ssyntax, objects, and namespaces/import as plain-old Arc code is impressive. Very impressive. In fact, I don't know of any other language that can do that, though I've heard Smalltalk is very flexible.
Since most of the Arc compiler is actually in the Arc namespace (combined with having access to Racket), I get the feeling that you could do almost anything with ar, which is most definitely not true of Arc/3.1.
