Friday, June 20, 2014

Reeborg in real life

One of the first users of rur-ple is a high school teacher in New Jersey who gave me some great feedback while I was developing the program.  He reall seems to have found a way to make students enjoy learning.  A while ago, he sent me this picture of one of his students who decided to make a Reeborg costume for Hallowe'en.

And, today, for the last day of school, another student gave him this as a token of appreciation:

Knowing that the little robot, whose image I drew pixel by pixel with my limited art skills, seem to have been appreciated by students as they learned programming using Python makes my day! :-)

Wednesday, May 21, 2014

Reeborg programming challenges - Challenge #1

Can you have Reeborg do multiplication without using numerical variables?

Reeborg must show that it can multiply two numbers by taking a number N tokens located at x=1 and  y=Y, and leave a single token at row y=1 and x = N*Y.  For example, here's a starting position (image taken from RUR-PLE, so that it looks a bit different from the web version)
the final position must be
where a single token must be deposited.

So, without using numerical variables, and using only a single instruction per line (so no use of semi-colon, or having a colon followed by a statement), how short can a solution to this problem be?  Here's an example of a solution that is NOT allowed under the above rules:
y = 1      # numerical variables not allowed
tokens = 0;turn_left()  # use of ; is not allowed
def turn_around():
while not token_here():  
    y += 1  # not allowed
while token_here():
    tokens += 1  # not allowed

while front_is_clear():  move()  # not allowed, statement after colon

repeat(move, y*tokens-1)  # not allowed, multiplication

The solution must work for 5 different challenges (mul5x1, mul1x5, mul5x5, mul4x3, mul3x2) - or any other such challenges for which I could create a world. Excluding the line with think(0), which makes Reeborg move as quickly as possible, and the line select_challenge(...), can you write a solution shorter than 29 lines?  Solutions can be attempted at Reeborg's World. You may want to click on the help button to see a brief summary of all known instructions.

Le monde de Reeborg: finalement en français!

J'ai finalement complété la traduction de la nouvelle version du monde de Reeborg en français. Les tutoriels pour débutant, que ce soit pour Python ou pour Javascript ne sont cependant pas encore traduits.

Si la version française vous intéresse, svp contactez-moi par courriel (ou laissez un commentaire sur ce billet) pour me le laisser savoir et que je puisse mieux juger du besoin de traduction des tutoriels.

Thursday, May 15, 2014

Eating your own dog food

When I created rur-ple, my intention was to use it to teach my pre-teens computer programming.  When it was working reasonably well, and after having written a few lessons, I showed it to my daughter who quickly went through the material I had prepared and concluded that it was too easy/boring.  She essentially decided then that programming was not for her.

Fast forward 10 years.  She had to do some programming as part of her university program and found out that she really enjoyed it.  She is currently more than 1000 km away, working in a lab where she has to program in Python, which she is essentially just learning.  She had a question for me, emailed me some code when I got the idea of using Reeborg's world's editor and the embedded TogetherJS from Mozilla so that we could share a screen, while talking using Skype.  

It worked very well. :-)   However, I found that, while the fixed-size editor was big enough for the tutorials I wrote, it was too limiting when trying to work collaboratively on "real life" code.  The same could be said for the output area ("Reeborg's Diary"). Nothing like "eating your own dog food" to find its limitations.    So, after a couple of hours of tinkering with javascript/jquery/css, I finally got a reasonably working setup for remote collaboration/help on Python 3 code (using Brython) or Javascript or CoffeeScript or .... (more languages to come eventually).

The only limitation that we found is having the TogetherJS chat window in a fixed position. If it could easily be moved (on a per-user basis), it would make it even more useful.

Tuesday, May 13, 2014

Python tutorial for beginners.

The first draft of my Python tutorial for beginners is now live.  The previous link is for the tutorials; the actual code needs to be entered in Reeborg's World.  There is also a Javascript version of the tutorial.

Tuesday, April 29, 2014

Collaborate on Reeborg's World using Mozilla's TogetherJS

If you go to and click on "Start TogetherJS" at the top, you can get a URL to share with others.  This hopefully will be found useful by teachers who can help their students remotely.

Note that the exact location of the Start TogetherJS button may change in the near future.  Thanks to Ian Bicking and others at Mozilla for creating this amazing tool.

Feedback is welcome! ;-)

Reeborg's world: more options to share

RUR-PLE's primary goal was to create a very easy path for people that wanted to learn programming.  The original version still had a significant hurdle to jump over for absolute beginners.  They had to 1) download and install Python; 2) download and install wxPython; 3) download and unzip the files for RUR-PLE's distribution.  This is probably considered to be trivial by the reader of this blog ... but it was not so for the users (some of whom were young children ... or their parents!)  So, it really required to have someone nearby with some computer savyy and, since it required to install programs, some teachers could not use it without jumping through additional hoops to have it installed on the school computers.

As more users joined in, some volunteered to create "one-click" install files (.exe, .dmg, etc) for various systems.  These were made available on Google code; however, since new downloads can not be added (due, I understand, to how this service was abused by some other "projects"), this means that yet a new home (after the original sourceforge site) would have to be found for updates.  Furthermore, this does not solve the issue of installing software on school's computers.

These various facts were the main impetus behind my desire to create a web version as something with the absolute lowest barrier to entry.  To my mind, this means no creation of user accounts.   With no user accounts, there is nothing saved on the server.  Still, it is useful for people learning to program to be able to save their results.  So, I implemented:

  • An automatic save of a program state when it's run successfully.  This includes the code in the "library".  It also saves the "world" that was selected, as well as the programming language (Python, Javascript of CoffeeScript). This way, when a user returns to the page, it restarts from where it was left off.   However, this uses localStorage which is appropriate only when everything is done from a single browser.
  • For students that may want to work on the school computer and at home, I implemented a way to save to files (hello USB keys...); this can be either the world selected (which the student can edit) or the program or the content of the library, each saved separately.
I thought this was going to be enough until I got an email from the Samsung folks behind the Junior Software Academy initiative.  As I mentioned in a previous blog, they created a book based on rur-ple.  They now would like students to take part in a mini programming contest and wanted to be able to have the students show their results.  This works fine if rur-ple is installed on the computer they have ... but a web based solution was thought to be more interesting. So, I implemented a permalink utility which enables one to save the complete state (programming language, world definition, code in editor and library) and share this as a url.  Here is a silly example.  

One more thing I would like to do is to implement a collaborative mode using Mozilla's TogetherJS.  However, this will require quite a bit more coding, based on what I saw in an earlier attempt, just after TogetherJS was announced.