arc> (= ((foo (quote bar)) (quote baz)) 42)
  42
  arc> (= (foo!bar 'baz) 42)
  Error: "Can't invert  ((foo (quote bar)) (quote baz))"

   (def expand-metafn-call (a b) (cons a b))

The problem appears to be that the current '= was meant for use with the older ssyntax, which supports only : for composition. I'll take a better look maybe later, I'm just home from work, cooling off (very hot in the philippines right now)

The "invert" thing is really confusing, I didn't add docstrings to all the '= related stuff because of that. Me, I say refactor '=. LOL

Edit: Fixed on the git.

  (def metafn (x)
    (set x (ssyntax x))
    (and (acons x) (in (car x) 'compose 'complement)))

Also, thanks for reading over my little gotchas that I found in the srv.arc documentation and updating them so quickly on your site. I hope the comments helped out. I'm just about to sit down with the app.arc docs for a bit of enjoyable reading before bed :-)

As far as identical titles "Headers + Redirect" for defopr and defopr-raw, I'll take your suggestion and change defopr's title to "Redirect", even though the truth is more complex. The way they work:

defop: takes req as argument, body prints HTML

defop-raw: takes (stream req) as arguments, body prints headers, blank line, HTML

defopr: takes req as argument, body prints headers, returns (not prints) redirect path

defopr-raw: takes (stream req) as arguments, body prints headers, returns redirect path

Everything seemed straightforward between the plain and the -raw macros, until I realized that defopr and defopr-raw both let you modify the headers. So the only difference is defopr-raw uses an extra stream argument, which hardly seems worth a separate macro.

So if I were in charge of Arc, I'd get rid of defopr-raw and arformh, and I'd drop the stream argument from defop-raw.

The biggest problem with using Ajax is that the Arc web server doesn't support .js files, which is a big oversight for a web-targeted language. Consider this a bug report suggesting support for .js static files. (Really the design should allow arbitrary static files with arbitrary mime-types, rather than hard-coding the list.)

And there's a typo on your page: you don't close the code tag around "/getcontents?field=population&name=value", so the rest of the page is in monospaced font.

Same with defop. Accessing the GET/POST arguments to an operation is done via (arg req "foo"). It would have been worlds nicer if I could just define something like

  (defop foo-getter req
   (w/args (foo bar) req)
     (...))

  (prn "kens" #\@ "arcfn.com")

Actually I'm talking about so-called "combining characters" http://en.wikipedia.org/wiki/Combining_character