Friday, August 2, 2013

A python interactive console in my blog

Brython modes

I had prepped a presentation on Brython for a Python conference and didn't want that to go to waste, so now, dear reader, you get to see all kinds of exclusive material I had made for it. (Don't worry, I'll have plenty more material for PyCarolinas 2013).

The difference is that this is a blog, not a talk, so it will be a good bit more non linear. I'm starting tonight with something very hands on, one of Brython's mode of deployment.

The Brython interactive mode

The brython.js script itself is not included in this page, so it is a hosted interactive mode. We will simply include an iframe to load an interactive console directly from This is still quite experimental, as it is found under the tests/ section. It is now using most of my iframe box (was fixed some days back). But it does work pretty well already.

This is basically a zero install, just add the following in your web page and you'll get a brython interactive session (Edited 3-26-2014 to point to new location):  

<iframe src="" width="98%" height="400">Sorry... your browser doesn't support iframe. Time to upgrade or go to <a href=""></a> in a separate tab.</iframe>

So you should see a console above (wont work trough news aggregators). At the >>> | prompt, type:

x = input("yo")

Type the word me in the prompt dialog that will open. Make sure you type exactly that. So what do we have in x? Type the following:


me - Ok, that's all nice, but not very exciting. So it does behave like a console. What else can we do?

import webbrowser

So now we have loaded the module webbrowser from the brython standard library (we will come back to that in a future article). Yeah, I know, mind bending, since we are client side. Let's use the module. Type the following:"" + x*2)

Nice! All your base are belong to us, obviously. So, it does take a minute to get the brain wrapped around this concept, but once you do, the world's your oyster. You just have to:

doc <= "think"

Alright, enough geek puns, but it is a friday night afterall. So go and check it all out at . There is documentation in english, french, spanish and portuguese. Feel free to contribute your own translations in markdown format through bitbucket.

If you've been following my blog, you already know about the <= (left arrow) operator. If not, check it out here:

In the early days, brython didn't have a print() keyword. So I had cooked up a quick webprint() that used the <= operator. Of course, 8 months later, we no longer need webprint(). Print works like it should, with stdout. For the interactive mode, it is redirected. Look at the (python) code to see how you can do that by right clicking on the iframe and doing a view frame source (hint, lines 48 to 51).



Joe said...

Brython is coming along nicely. Now I'm wondering if it can be interfaced to something like AngularJS and how difficult/easy it would be, pros and cons ...

Dirk said...

Great! Even 'import antigravity' works!