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Your own Arc REPL, online (dabuttonfactory.com)
16 points by palsecam 3655 days ago | 11 comments


5 points by palsecam 3655 days ago | link

Fellow Arcists,

May I present to you the evsrv (eval server), a multi-user, multi-tasks, shared time "Arc Machine"!

Once you've created an account, you're in front of our own Arc REPL, with your own environment (i.e: you can define stuff, and state is preserved between requests & logouts-logins).

It's all new, so expect bugs & problems. Plus, I'm not quite sure it can stand on the long term, even more on this small server (single core, 1gb memory, and already running, as you can see, http://dabuttonfactory.com).

Oh yes, and forgive me for the URL, I may buy a domain name for it, but I thought you might like to play with it even in its "alpha" stage ;-)

It runs on a modified version of Arc, that uses some extra MzScheme stuff, mainly namespaces & sandboxes. I may post the source, but like for the domain name, not now. Want to see if it works on the wild before.

Please don't spam it too much for now, I mean don't tell all your friends. But play with it for yourself as much as you want ;-)

Suggestions, ideas, bug reports are greatly appreciated.

Happy hacking on your browser!

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3 points by s-phi-nl 3655 days ago | link

Thanks for this, even though I haven't used it yet. I've been using the ArcLite online demo (http://jonathan.tang.name/files/arclite/index.html), but it hasn't been maintained; its creator, nostrademons, hasn't been very active; and it is so slow that the fizz-buzz problem fails to run on it.

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2 points by palsecam 3655 days ago | link

Gosh, and thank you for the ArcLite link! I didn't such a thing (Arc in JS) already exist, and it's actually a thing I plan to (maybe) work on!

Don't know what the "fizz-buzz" problem is, but if you test it on evsrv, please let me know if it works ;-)

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2 points by rntz 3655 days ago | link

I would very much like to see the source, even if it has bugs or scalability issues or whatever.

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1 point by palsecam 3652 days ago | link

Sorry I don't come back on the "want to see if it works on the wild before". I'll certainly show the source, even if it doesn't (work on the wild), but please wait.

Plus, hmmm, did you even bother trying it? You may have chosen another username, but:

   arc> (user->repl* "rntz")
   nil
If you have chosen another username, OK, no problem (but I can't guess). If you've not tried it, your choice, but then I'll parse your request as "Gosh palsecam is such a moron, an REPL on the browser has no future[1], performance/privacy issue, blahblahblah, but I'll be glad to steal his code for another more useful purpose that I'll not communicate about".

I am, at least I hope, certainly wrong on my analysis, but sorry, that's how I read your message. And obviously, I don't like to be taken for a moron. And obviously, I don't like this kind of "stealing".

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1: I'm sure some people think this. They might be right, but this kind of reasoning also lead to "GMail/... has no future", which was proved to be wrong.

I don't know if I'll seriously keep on working on the evsrv, but I can think of lots of good features that being web-based would enabled.

rntz, if you think this is a stupid idea, I have no problem with this, but then tell us about the (better) idea for which you'd like to use the code.

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4 points by rntz 3652 days ago | link

Wooooah. You have totally misinterpreted me here.

It's true I don't (well, didn't) have an account on the eval server. I didn't really feel the need to try it, not because I think it's crap, but because... well, it's a persistent REPL on the web. That's most of what I need to know, really, and if I ever need a persistent web-based REPL I'll know where to go - I trust it to be everything you say it is (and now that I've looked at it, it is; and it's swanky to boot). Just because I don't yet have a use for a thing doesn't mean I think it's crap. Hell, I don't yet have a "real" use for Arc itself beyond just playing with it as a sort of language sandbox - I haven't even tried firing up the webserver that comes with it! Does that mean I think arc or the arc webserver is crap? Hell no.

I have no intention of stealing your code. If you don't want to share your code, then don't; I tend to assume that Arc-related stuff will be open-source simply because it's common. And if you do share your code, I won't use it for some private purpose that "I'll not communicate about"; I'd share it back. That's how open source works.

The reason why I asked to see the source, despite you noting that you didn't intend to release it until testing it in the wild, was because I imagined (as CatDancer seems to have surmised) that the reason you didn't release it was because you weren't satisfied with its quality yet; hence the comment about "even if it has bugs or scalability issues or whatever".

The reason why I want to see your code is not, then, because I think you've done a bad job - how could I? As you noted, I hadn't even tried it when I made the post. Rather, I'd like to see it because in order to implement it, you have to have done some cool stuff (for example, AJAX, and some way of maintaining a persistent REPL) in arc that I would find instructive to read and possibly useful in the future. I don't ask with a purpose already in mind, but rather to learn; that's why I'm using Arc in the first place.

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3 points by palsecam 3651 days ago | link

Sorry I was a moron. Source available now, see http://www.arclanguage.org/item?id=10427

> Does that mean I think [...] the arc webserver is crap? Hell no

Actually, on some points it is (IMHO of course) ;-D

> I won't use it for some private purpose that "I'll not communicate about"; I'd share it back. That's how open source works.

Sadly everyone is not as honest as you :-/ I've met some people not understanding what FOSS is about, and being big bitches about it, so I'm now more suspicious than I used to be.

But this is no excuse, I was not right to emit judgements about you based on my past experiences.

> weren't satisfied with its quality yet

Yep, was/is the case, see last item on the TODO list (in evsrv.arc)

> some cool stuff (for example, AJAX

Actually, nothing cool or magic about Ajax. It's just sugar (here).

> some way of maintaining a persistent REPL)

More magic here :-) Although it is just because of MzScheme being a very good language, and having namespaces and sandboxes.

> I don't ask with a purpose already in mind, but rather to learn

The noblest of all purposes ;-)

Once again sorry for misinterpreted and being quite rude with you.

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4 points by CatDancer 3652 days ago | link

I think I may be able to clear up a bit of confusion here.

All (almost all?) of the code related to Arc so far has been released as open source by various authors, including rntz's extensive work with Anarki.

Thus when code hasn't been released, it's been because the author doesn't think it's good enough yet, instead of because the author wants to keep it proprietary.

So when one of us sees something cool, it's not uncommon for us to say, "oooh, we'd like to see the source to that!" Not as a request to give away something proprietary, but to say that if someone has code that they'll be making open source anyway, to encourage them to go ahead and release it, because it looks cool.

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2 points by fallintothis 3652 days ago | link

Wow. A bit of a heavy-handed analysis.

I'm pretty sure it was a statement of curiosity. I'd venture to say that that's the intention most of us would have in asking to see the source. (Hell, I'd be interested in seeing it.) You're probably reading too much into this.

(Plus, it's not really "stealing" if you willingly share the code.)

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4 points by fallintothis 3655 days ago | link

Sorry to be a pedant, but the paren-balancing is incomplete:

  arc> (string #\()
  ; can't send, even if I click the button instead of hitting "enter"

  arc> #\(
  )

  #\(
  Error: UNKNOWN::4: read: unexpected `)'

  arc> "("
  )

  "("
  Error: UNKNOWN::4: read: unexpected `)'
I tried this first, since I've noticed that syntax highlighters (of all things) often get this wrong.

Beside that point, very nice job. I especially like the interface: it looks great. My (light) testing yields no other bugs, at this point.

Also, not a bug, but a suggestion (tested in Firefox 3.0.8):

You might consider doing some line-wrapping of the output. For instance, when I just do sig at the REPL, it prints out the (large) hash-table just fine, but it's on one line, so the frame's dimensions stretch to accommodate it. The textbox for the prompt then centers under this wide line, and it's awkward to side-scroll to type more code and read further output.

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4 points by palsecam 3654 days ago | link

> Sorry to be a pedant, but the paren-balancing is incomplete

This is not pedantry, this is bug reporting!

Yes, the check for '(', ')'s is really naive, and to be honest, I don't feel like coding a decent Lisp parser in Javascript for now :-)

> can't send, even if I click the button instead of hitting "enter"

This was actually not a bug, but a desired feature :-D But this was totally stupid, since the '(' check is incorrect in some cases. Now, clicking the button will anyway send the content, no check done in JS. If your content is invalid, evsrv will tell you:

   arc-online> (    ; then click on the button
   Error: UNKNOWN::0: read: expected a `)' to close `('
   
> You might consider doing some line-wrapping of the output.

Yes, absolutely. This is now (partially) done. `sig' and the majority of cases will be correctly handled, but not everything. `(for i 0 1000 (pr i))', for instance, is still "broken".

The problem is, the results are inserted in <pre> blocks, and after some search, it's easy to make them break lines on whitespaces, but not otherwise (CSS property "white-space").

Plus, a small bug I just recently noticed has been fixed: evaluating "nil" or "()" or "#f" didn't work. It now does ;-) But:

   arc-online> #f
   nil
   arc> #f
   #f
But remember this is the eval server:

   arc> (eval '#f)
   nil
So this is actually quite normal ;-)

Oh, and I tried the site today with Safari, and it globally works but the layout is bad. I'll fix this ASAP.

Anyway, thanks a lot fallintothis for your feedback! Testing these edge cases was smart of you ;-)

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