https://github.com/Pauan/nulan/tree/1566c941d47d5c39609a8097...

The first change is that it now only shows the output for the top-level expressions that are selected. To try this out, first input this:

  var foo = 5

  foo

---

The second change is that I added in a sandbox where you can do DOM stuff interactively. To test it out, input this:

  w/var x = document.create-element "div"
    | x.style.background-color <= "green"
    | x.style.width <= x.style.height <= "50px"
    | x.add-event-listener "click" ->
        alert "Hi!"
    | document.body.append-child x

---

At this point it's already a nicer experience than entering stuff into the REPL. But I can do better. I plan to add in CodeMirror[1] support for the textarea on the left side, and add some more polish and such.

https://github.com/Pauan/nulan/tree/fc8003fc6c238540839a852b...

http://codemirror.net/demo/widget.html

I was able to very easily add in inline error messages to nulan.html:

https://github.com/Pauan/nulan/tree/a24a33a864d9e2800fc3c995...

And here's a screenshot of it in action:

http://img687.imageshack.us/img687/2348/screenshot1223201203...

https://github.com/Pauan/nulan/tree/9ffecb5a9aa7a4bd7cbe9680...

Firstly, there's now an interactive tutorial. Just open up "nulan.html", and if you don't see the tutorial, click the "Reset Tutorial" button at the top. Be careful, it'll clobber any changes you've made.

Secondly, you might have noticed that the editor has syntax highlighting now. But it's actually really cool. First, try inputting this:

  $mac foo -> a b c
    a + b + c

  foo 1 2 3


  def foo -> a b c
    a + b + c

  foo 1 2 3

Now try inputting this:

  # Array comprehensions
  box in

  $mac for -> x {('in) n y}
    'y.map -> n x

  $syntax-infix for 0 [ order "right" ]
  $syntax-infix in  0 [ order "right" ]

  (x + 2) for x in {1 2 3}

  $mac ^ -> a b
    a + b

  $syntax-infix ^ 0 [ delimiter %t ]

  prn 1^2

http://pauan.github.com/nulan/doc/tutorial.html

I'm thinking about putting in a redirect for the old URL, but I'm not sure if it's worth it or not.

https://github.com/Pauan/nulan/tree/f88a81563fec518cd740302d...

Or just use the uploaded version:

http://pauan.github.com/nulan/doc/tutorial.html

You'll have to use the "Reset Tutorial" button to see all the changes.

The biggest change is that you can now click on an expression to highlight it. To see what I mean, try clicking on stuff in the tutorial.

But the coolest part is that the highlighting understands boxes. Try inputting this:

  box foo = 5

  foo + 10


  box foo = 20

  foo + 30

  w/box foo = 5
    | foo + 10
    | box foo = 20
    | foo + 30

It's also smart enough to know that the "." syntax is a string, even though it looks like a symbol:

  box foo = []
  
  foo.bar <= 5
  
  foo.bar

a) if-box is a kinda contrived example. Perhaps we can find something better?

b) What's the difference between w/uniq and w/box? Both seem to create boxes. Could I just say this at http://github.com/Pauan/nulan/blob/5dfddacfbb/nulan.html#L44...?

  $mac if-box ->
    w/uniq temp
      'w/box temp = 5
         if temp
           temp + 1

  TypeError: Cannot call method 'chunkSize' of undefined

If you have a better suggestion, I'm all ears. But I settled on that because A) it's simple, B) it's short, C) it's something that does actually come up in practice, so it's not too contrived.

---

"What's the difference between w/uniq and w/box? Both seem to create boxes."

Well, to explain this... unique variables are actually implemented as anonymous boxes. So implementation-wise, there's not much difference.

The difference is in the actual macros "w/box" and "w/uniq". Here's the definition for them:

  $mac w/box -> @args body
    'w/new-scope
       | var ,@args
       | body

  $mac w/uniq -> @args body
    'w/box ,@(args.map -> x 'x = make-uniq;)
       body

  w/box foo = 5
    foo

  w/new-scope
    | var foo = 5
    | foo

  w/uniq foo
    foo

  w/box foo = make-uniq;
    foo

  w/new-scope
    | var foo = make-uniq;
    | foo

They serve exactly the same purpose as "let" and "w/uniq" in Arc.

If you're asking why you can't just do this:

  $mac if-box ->
    w/box temp
      'w/box temp = 5
         if temp
           temp + 1

  $mac foo ->
    w/box bar = 5
      'bar + 2

I thought about having it throw an error for local symbols, which would have required you to write the macro like this:

  $mac foo ->
    w/box bar = 5
      ',bar + 2

---

"I tried running this and got the following"

It works fine for me. And in fact, the code snippet you posted seems exactly the same as what is already in the tutorial. Maybe you intended to paste something else?

I pasted your DOM demo code twice, and then I was able to access both window.x and window.x2 from within Nulan. Is this intentional?

I also appended some DOM elements to the parent frame using "window.parent.document.append-child x", and they didn't get cleared on each update, but that's my own fault I guess. :-p

Yes, absolutely. It's how Nulan ensures that every variable is bound to a single "box". This also has the nice property that all the different "versions" of a variable can be accessed from the JavaScript side.

Ordinarily you can't access the different versions from within Nulan, but "window" is one of the ways you can do so. Another way would be the "&" macro which bypasses the Nulan compiler.

---

"I also appended some DOM elements to the parent frame using "window.parent.document.append-child x", and they didn't get cleared on each update, but that's my own fault I guess. :-p"

Yeah, only the <iframe> is sandboxed. Of course you can refresh the page to clear it out. Don't worry, it'll save the text you typed in the textarea.

---

"How do you call a function with no arguments?"

Use ; like so:

  foo;
  foo.bar.qux;

As for socket.io... well, that's just a JS library, right? And Nulan just compiles to raw JS, so you should be able to interface with it just fine.

I mean Node.js gives JavaScript the side effect powers typical of OS processes, while the browser gives JavaScript a UI. With socket.io, it should be very easy to take your browser interface and use it as a command shell. I can help if you'd like. ^_^

---

"As for online hosting... no, not really. I mean, if somebody wants to host it, feel free, but I'd personally wait until it's all nice and polished first."

Alrighty. I'm still not 100% sure how you'd accomplish that, so I wouldn't mind some help.

---

"I was thinking of something easy and free like GitHub Pages. I understand if you'd like some more polish though."