You all probably knew where this was going, right?

Mind Traffic Control (Racket version) running on PocketCHIP
Mind Traffic Control (Racket version) running on PocketCHIP.

Of course, it’s been my priority to run the new MTC on the PocketCHIP. And it runs fine, without any special conversion; just needed to figure out how to install a library it depended on without going through drracket.

Now I’m off for my celebratory bike ride. 🙂




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Yahoo Pipes may be dead, but Node Red seems to be the device swarm orchestrating, data-flow programming tool I was hoping it might evolve into.

It’s free software, it runs on everything including RaspberryPi and talks pub-sub protocols like MQTT.


Source: Node-RED

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Third in a series (#1, #2) of questions occupying my mind at the beginning of 2014. Which may (or may not) inform what I’ll be working on.

3) How can we program on tablets?

I’m now a tablet user. I became a tablet owner at the end of 2012. For six months I played around with it, trying a few Android programming exercises. But I only really became a regular tablet user half-way through the year. Firstly when I put Mind Traffic Control into a responsive design. Secondly when I bought a couple of e-books. And I only really got committed when I did OWLdroid and coupled that with btsync.

So – somewhat late to the party, I admit – I’m now a tablet enthusiast.

And so my question is, how the hell do I program on this thing?

There’s a trivial answer to that question : get an external keyboard, an appropriate editor / IDE and treat it like a normal computer with a small screen. I can do that. I’ve worked a lot on netbooks and small screens don’t freak me out. But that’s not really what I mean.

Because tablets aren’t meant to have keyboards. And a computer without a keyboard challenges one of my deepest held programming beliefs : the superiority of plain text.

Plain-text is so flexible, so expressive, so powerful, so convenient to work with, that I’ve always been highly sceptical of those who want to do away with it. But on a keyboardless computer, it’s a different matter. Plain text isn’t at all convenient without a keyboard.

Especially the text of programming languages which makes rich use of another dozen or so punctuation symbols beyond the alphabet and numerals. And where manipulation relies on cursor-keys, shift and control, deletes (both forward and backspace), page up and down, tab-complete etc.

And yet tablets are becoming ubiquitous. Increasingly they’re the target of our programming, and the tool we have with us. So how are we going to program in this new environment? With multi-touch or stylus but no keyboard?

I have yet to see anything even vaguely plausible as the revolution in programming “language” we’re going to need for this.

I don’t think it’s the “Scratch”-like or “App Inventor”-like “stick the blocks together” languages. The problem of programming on tablets shouldn’t be conflated with the problem of teaching novices to program. (Which is what most visual programming environments seem to be about.)

One issue with that kind of system (and other “flow-charts”) is that blocks need to be big enough to be easily and unambiguously manipulated with fat fingers. But to be decently usable, a programming system should be able to have a reasonable density of information on the screen, otherwise you’ll spend all your time scrolling and forgetting what you’ve seen. How do you resolve that tension?

Perhaps “data-flow” programming of the Max/MSP, PD, Quartz kind. Piping diagrams. Process Modelling packages have something to teach us about orchestrating in the large. But they are shockingly clumsy for certain fine-grained activities that are expressed easily in text. (Eg. how the hell can you talk about tree-shaped data or recursive algorithms using this kind of piping model?)

So I don’t have any information about who is doing interesting work in this area. (Aside : while writing this post, I thought I’d consult the collective wisdom on StackExchange. Needless to say, my question was immediately shot down as too vague.) But I’m now very curious about it.

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Quick Note : I just had a revolution in my thinking, triggered by Enso but influenced by several other recent trends.

You write Enso “extensions” as XML-RPC servers sitting on your local machine, register them with Enso and it calls them using XML-RPC. I tried the example from the tutorial and it’s very cute and simple. So I’ve decided this may be a way forward for the dilemma which has kept the “new SdiDesk” on hold for several years(!!!)

If you remember, the issue has been whether the new SdiDesk should be a “web”-application (accessed through the browser) or a desktop application? And how to implement the UI.

The problem with the “browser” answer has always been : “but how to do the network diagramming bit?” – which requires interactive vector graphics. SVG doesn’t seem quite stable or cross-browser enough. Canvas isn’t cross-browser. Flash is proprietory.

The problem with the “desktop application” is, well, the many rival Python GUI libs with different degrees of maturity. And the question of getting them to work cross-platform.

A meta-problem : I just don’t have time and energy to go through learning lots of different GUI frameworks to decide which I want to use. And the ideal answer to the browser / desktop question is probably “both” which doubles the amount of work.

In fact, one of the motivations for GeekWeaver is to see if I can use it define a higher-level UI description that can be compiled down into both XHTML and a GUI widget-set.

Of course, with XUL, Open Laszlo, Adobe Flex, XUML etc. lots of people have been looking at something like HTML for defining desktop apps. too, but the free Python frameworks don’t seem to have caught up with that yet. XUL sounds most promising especially with the open sourcing of Active State’s Komodo … but that’s also a big complicated thing to even start looking into.

Anyway, inspired by the Enso extensions and Bruce Eckel’s interesting example of hooking up a Python XML-RPC server behind an Adobe Flex application I’ve been wondering about blowing the project apart entirely into a number of services connectd only XML-RPC or something more ReSTful.)

So there’ll be a WADS (SdiDesk PageStore) service, a GeekWeaver interpreter service, a “user navigation history service” etc. Even the glue which ties all this together will be another service that’s neutral about the user-interface. Effectively the model, view and controller will be completely separate programs. (I know, I know 😉 )

Then there’ll be a variety of different types of access with different UIs.

Now that Adobe’s AIR has put Flash on the desktop and made it a serious rival to the Java virtual machine – I *am* tempted to put some time into learning it. It would give me a reasonable GUI widget set (including TreeGrid, yay!) and the vector graphics needed for networks. It will run both on the desktop and in the browser and on Linux, PC and Mac. The tools are free-as-in-beer (Flex beta) or free-as-in-speech (Open Laszlo). It’s also possible to imagine generating the Flex XML or the Open Laszlo format directly from GeekWeaver. (Aside : I wish ActionScript hadn’t borrowed quite so much from Java, but still, I’d only be using it for the front-of-the-front-end UI stuff.)

Then I want to experiment with Enso access – for example, Enso commands like “page HelloWorld” or “pagehistory ChocolateCake”

And there’ll be web-browser access probably through a “gateway” that accepts http requests and spits out HTML for a browser. The only thing I don’t know is whether I *really* should be using WSGI somewhere here.

Anyway … that’s a quick update of my thinking this week … tune in soon for the next GeekWeaver release (really, it’s coming together, and gonna be very powerful). Then it’s back to work on this larger project.

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