The 'Datafy' and 'Nav' protocol interfaces look really interesting.
From what I gather using those along with Clojure 'Spec' allow you to create ad hoc, generalized interfaces as an abstraction layer accessing an infinitely large lazy tree of 'things' (provided these 'things' are data or can hold meta data).
Unfortunately I have yet to see anyone really use it in the way I imagine it can be. I'd like to see a web 'req' var with the ability to drill down through the server-code<->js-code barrier (via the session and connection protocol) all the way down into the dom and the js application state. That would be really, really cool.
Also, I've been building a general purpose app builder (for web apps). This app building process is currently working, but in the future I'll need build a more advanced inspector and a designer. Since my stack is Clojure from server to js I'm wondering if it makes sense to build the inspector on top of that trio of technologies then attach the designer to it.
Someday I'll get to do that! ... I just know it. :)
Edit: for those who wonder what this has to do with REBL... these are the core technologies that REBL is built upon.
I've used it in production at multi-national organizations.
In fact that's how I learned to code. 10 years ago I was a business analyst who couldn't get the dev group to work on my projects in a timely fashion. The ability to use arc was in reach for me, even though I had no programming experience at all.
I actually wrote and released 2 internal apps and 1 external app that had good use (a few hundred users using it daily/weekly to get their jobs done). This was in production for a few years until I left in 2012. I'm pretty sure they're not using these apps anymore.
> What sorts of systems would it excel in and what sorts would it be unsuitable for?
I think its primary strength is the short learning curve. I also I think it's unsuitable for anything which needs to use existing db connections. Even though I did hacks to make that work it's the primary reason my apps could not be adopted by the dev group.
> What could be done to alleviate for Arc’s lack of features?
* better db integration
Or if there's no interest in db integration then make it focused on compiling to js for mobile devices where db integration is less of an issue.
> In fact that's how I learned to code. 10 years ago...
It's kind of ironic my first post was about a most recent topic:
"After playing for a bit I noticed my "set x" functions were
clobbering each other...so I started converting all my function to use
"why wouldn't the ARChitects of LISP or ARC make a set like
function that is global within a function ?
This definitely not great, but having to use 'with' is not the real issue for me. In fact if you read through the code you'll notice that this style is often used deliberately (i.e. some people might argue that it's a feature).
I think the bigger issue is that global vars can be used without any errors or conflict warnings. So someone else can create code which sets globals which then gets loaded via libs and will pollute your program. So you could have lib#1 set var 'x' only for it to get clobbered by lib#2's version of var 'x' and arc just ignores this. That's bad. Really bad.
>So you could have lib#1 set var 'x' only for it to get clobbered by lib#2's version of var 'x' and arc just ignores this. That's bad. Really bad.
And how often is it intended behavior? How often does one want to have a macro parameter or apparently "local" variable overwrite an existing symbol globally and arbitrarily?
I can see it being useful in the case of "hot patching" code to just redefine a function, but that's still kind of crazy, since now the source code and running code are no longer the same. Might as well just edit the file and reload it, and have one source of truth.
It seems like an anti-feature. Something that seemed like a good idea in theory, but which in practice does more harm than good.
I'm not following the two of you on precisely what this anti-feature is. Assigning to local variables using '=' does not create new global variables. Can you share a code sample showing what you're talking about?
>This is where js would be handy - right? Personally I would just update the dom element and send a http post in the background.
If it's to be done in JS, might as well implement a drawing tool in an actual canvas element.
I've seen tutorials that are reasonably simple. The complicated part would be actually saving it. It is possible to export a canvas as a png and upload it with an AJAX request but I don't know how cross-browser compatible that is.
We started out by making an EventSource endpoint and using JS EventSource object to get updates. Seemed to work great.
Pushed it live.
To everyone on the site. Not just to the people on /l/place. Oops. Mistake #1.
Mistake #2: I was aware that Arc kills threads that take longer than 30 seconds, but I was unaware that EventSource automatically tries to reconnect. Welcome to the DoS party.
With no way to tell the clients to stop. Mistake #3.
It was only live for about 10 minutes, but it took around two hours before the last few clients finally refreshed their browser and stopped DoSing the endpoint. The server absorbed the extra traffic like a champ, but the server logs were ridiculous for about an hour. Lots of "client took too long" error messages spit out by Arc every second.
Sooo yeah, submitting changes via JS is easy. Getting updates is the hard part.
Could poll. But then that's still hammering the server. Moreso than it already is.
It's probably a feature that it's painful to use. Only the determined will use it for art.
That said, if anyone has ideas for how to tweak arc for performance for this scenario – and remember to calculate how much memory is used by how many simultaneous sockets are open – I'd be willing to try again.
> I was aware that Arc kills threads that take longer than 30 seconds...
> Sooo yeah, submitting changes via JS is easy. Getting updates is the hard part.
That's why I suggested a post request...
Just deliver the page and create an api end point, on the server, that gives you the last x changes from the change log.
With that ajax request, you could return these net updates for the client and use client side js to apply them to the dom. You could even create a trivial js debounce algo to throttle requests if you wanted to go even further.
I will say; I did a page reload and noticed the color pick was still in place and had to go hunt for the x. I expected it to reset, but I'm not sure if you see that as a bug or a feature :)
also, it looks like the client side is pure js... Is Lumen not up to that task? just curious if you tried that as it might be nice if, someday, we could get to the point where this kind of stuff could be done in arc.