I added some libs to my local kojo env. Perfect.

But the log information coming from those libs is ignored or at least I'm not able to find.

Can someone guide me to how I can get that working?

Cheers, Volker.

If I enter:

 def minmax(x: Int, y: Int): (Int,Int) = { if (x > y) (y,x) else (x,y) } 

Single line functions don't seem to trigger this behavior. Also it doesn't happen if I've just opened the Scala Tutorial story and cleared the editor.

Is there some way of entering this "full sala" mode without opening the Scala Tuturial?

Thanks and I greatly enjoy this tool BTW!

Steve Harris and son

Thanks,

Craig.

Anyway, thanks you for making Kojo available, it's a great environment for teaching kids how to program. I teach physics (with electronics and computer science stuff) in a French high school in Paris. I've used differents langages and environments (pascal, C, python, smalltalk Squeak,DrRacket scheme) during the 10 last years but I want to switch this year with scala as langage and Kojo as IDE.

From my experience when teaching programming to kids (secondary school, 13-18 years old) you need:

1. a good langage:
- a simple and concise syntax (scheme,smalltalk, python and scala are good)
- algebraic notation like usual math notation (python, scala)
- real functional programming is an advantage since many concepts are already seen in math (scheme, scala, python)
- high level data collections as list, set, dictonary (hash table)(scheme,smalltalk, python, scala)

2. a good environment:
- an interactive Read-Eval-Print Loop (scheme,smalltalk, python, scala)
- friendly debug system, stepping… (DrRacket scheme, Squeak, Greenfoot)

3. Fun: graphics programs, drawings, sprites games (DrRacket, Squeak, Greenfoot, Kojo)

Bonus:
- interactive geometry with integration of geogebra (Kojo, Mathpiper)
- C.A.S. Computer Algebra System (Mathpiper)

Considering both the langage and the environment, Kojo is a great chalenger.
In my point of view, inspiring environments for kojo would be:

DrRacket:
http://racket-lang.org/
http://docs.racket-lang.org/quick/index.html
http://world.cs.brown.edu/
http://www.htdp.org/

Greenfoot:
http://www.greenfoot.org/

Mathpiper: (interactive geometry and computer algebra system in a functional programming langage).
http://www.mathpiper.org/

Xavier Coolen.

Is there any chance of introducing animation of 2D or 3D models with connections, movement, and forces like gravitation and magnetism?

Is it possible to use a more full featured IDE, like Eclipse, with Kojo?

Thanks,
Mushtaq

PS: Thanks for making this amazing tool!

I’m using Kojo to teach kids programming in Sweden.
I think the environment is great!

I would like to test if a key is pressed or not (without haning) in order to enable the kids make easy games where they control the turtle in realtime using the keyboard.

Is there an easy way of doing this?
I tried to look in codecompletion for Staging. , but found no keypressed etc as there seem to be in the corresponding processing environment: http://www.processing.org/reference/

Anyway of polling the keybord with the builtin stuff?

Cheers
Bjorn

Instructions for building Kojo with Netbeans 7 are available here:
http://code.google.com/p/kojo/source/browse/Build.txt

The older version of Kojo (which ran on the Netbeans 6.8 Platform), now lives on the NB6.8-scala2.8.x branch (http://code.google.com/p/kojo/source/browse/?r=NB6.8-scala2.8.x).

Thanks in advance

Marco

At this point, I'd appreciate feedback and suggestions: does it explain the right things the right way?

Kojo can definitely benefit from Network Collaboration/Competition/Gaming features. Here are some ideas on things that we might want to see within KojoNet:

• A Code Exchange - to share code/sketches, rate them, and discuss them (under active development)
• A Code Competition area - where users upload their competition entries during a specified competition time-range. These entries are then judged to declare winners (it should be easy to adapt the code exchange technology to implement this).
  • Competitions could be:
    • Programming puzzles,
    • Or Programming games like the one mentioned here some time ago by Peter. I'm not quite sure whether the game that Robert describes (in the link at the beginning of the post) falls in this category.
  • There are privacy and security issues involved with implementing competitions (as mentioned by Robert)

How do these features sound?
One great thing, in my mind, about the above features is that - I can see them getting implemented relatively quickly!

What other features can we think of?

In terms of implementation, here's the technology being used for the current cut of the Code Exchange:

• Scala XML literals for web templating
• The Play Framework (version 1.1)
• JPA/Hibernate
• Postgresql
• A slice on Linode.com for deployment

It should be relatively easy to run this stuff on the App Engine, if we decide to go in that direction.
If there's interest in hacking on this code, I'll set up a repo on Google code. Lemme know?

That's it for now - just a few rambling thoughts before I crash for the night. Feel free to pitch in with ideas…

 val ROUND = 360 val SIDE_NB = 5 val ANGLE = ROUND / SIDE_NB clear jumpTo(0, 300) write("Pentagon") jumpTo(0, 0) setAnimationDelay(42) setPenColor(blue) setPenThickness(11) for (n <- -2 until 3) { setFillColor(color(0x80 - n * 40, 0xFF, 0x80 + n * 60)) setHeading((2 + n) * ANGLE) repeat (SIDE_NB) { forward(150) turn(-ANGLE) } } 

There is something that puzzles me: if I replace the for loop with:

 var n = 0 repeat (5) 

 error: missing arguments for method repeat in object Builtins; follow this method with `_' if you want to treat it as a partially applied function repeat (5) ^ 

BTW, if I want to print a number in hexa style, what is the idiom in Scala?

Ideas:

1) Have a set of tasks to complete! I believe this is a great idea and should be central point of Kojo.

2) Create sharing area. Kojo could have "upload" button that will put example on some website with a screenshot.
Importing examples to Kojo should be easy as well.

2a) To improve 2) some ranking system should be created. [maybe something like StackOverflow.com would work]

3) Kojo should by injected to computer courses in some high schools to find its weakest points as learning platform.
Important: the teacher should be someone unfamiliar with Kojo, but familiar with programming

I don't see anything more important than the above for future of Kojo.

If you wish to contribute to Kojo, you are requested to sign the Contributor License Agreement. Please download the agreement from the link above, and then scan and email a signed copy of the agreement to pant.lalit at gmail.com, as per the instructions below:

• Put your initials at the bottom right of the first page.
• Fill out the required information and sign on the second page. Make sure you specify your country of residence within your mailing address.
• Email both pages as attachments within a single email.

The agreement is derived from the Sun Contributor Agreement – version 1.5

Links:

• code: http://code.google.com/r/peterlewerin-staging/
• reference: http://lewerin.se/peter/kojo/staging.html
• wiki: http://code.google.com/p/kojo/wiki/StagingModule

Original message (which all the replies are about):

Announcement: I've committed a small update that changes and extends the set of random number commands (start small!).

I replaced the randomDouble() command by an overloaded random(), added a randomFrom() command that picks a random member from a sequence, and added a randomSeed() command that sets the generator to a known sequence of numbers.

I've made a slight change to ScalaCodeRunner.scala; in Builtins I changed the declaration of Random and added two methods:

  private val Random = new scala.util.Random import scala.math._ def random[A] (upperBound: A)(implicit n: Numeric[A]): A = { val ub = n.toDouble(upperBound) if (upperBound.isInstanceOf[Int]) (Random.nextInt(ub.toInt)).asInstanceOf[A] else if (upperBound.isInstanceOf[Float]) (Random.nextFloat * ub.toFloat).asInstanceOf[A] else (Random.nextDouble * ub).asInstanceOf[A] } def random[A] (lowerBound: A, upperBound: A)(implicit n: Numeric[A]): A = { val lb = n.toDouble(lowerBound) val ub = n.toDouble(upperBound) - lb val r = lb + random(ub) if (upperBound.isInstanceOf[Int]) r.toInt.asInstanceOf[A] else if (upperBound.isInstanceOf[Float]) r.toFloat.asInstanceOf[A] else r.asInstanceOf[A] } 

If I can't get it to work I'll try reverting the change, but it doesn't seem likely that the above should be causing the problems mentioned.

Any ideas?

EDIT: I've reverted to revision 175 of KojoEnv now, and that actually made the reports about Point go away, but NB still can't find RunContext or CodeRunner unless I open core/codeRunner.scala in a window. And nothing I do makes the instance method visible, apparently. Curious.

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 import java.awt.Color._ def sq[A](x: A)(implicit n: Numeric[A]): A = n.times(x, x) def dist[A](x0: A, y0: A, x1: A, y1: A)(implicit n: Numeric[A]): A = { val v = n.plus(sq(n.minus(x0, x1)), sq(n.minus(y0, y1))) val r = Math.sqrt(n.toDouble(v)) if (v.isInstanceOf[Int]) r.toInt.asInstanceOf[A] else if (v.isInstanceOf[Float]) r.toFloat.asInstanceOf[A] else r.asInstanceOf[A] } clear invisible Canvas.fgClear //? val width = 200 val height = 200 // background(0) val maxDistance = dist(width/2, height/2, width, height) val distances = Seq.tabulate(width, height){ case (i, j) => dist(width/2f, height/2f, j, i)/maxDistance * 255 } for (i <- 0 until(height, 2) ; j <- 0 until(width, 2)) { val c = distances(j)(i).toInt Canvas.setPenColor(new Color(c, c, c)) Canvas.point(j, i) } 

 import Math._ import java.awt.Color._ clear invisible val width = 180 val height = 25 val halfwave = Vector.tabulate(width){ i => toRadians(i) } def render (level: Int)(fn: Double => Double) { val y0 = level * height val y1 = (level + 1) * height (halfwave map fn zipWithIndex) foreach { case(e, i) => val c = e.toFloat Canvas.setPenColor(new Color(c, c, c)) Canvas.line(i, y0, i, y1) } } val f = { x: Double => 1 - x } render (3) { sin } render (2) { sin _ andThen f } render (1) { cos _ andThen abs } render (0) { cos _ andThen abs andThen { x => 1 - x } } 

turn (angle)
dragon (depth-1, angle.abs)
turn (-angle)

turn (-angle)
dragon (depth-1, -angle.abs)
turn (angle)
}

clear
setAnimationDelay(0)
setPenThickness (7)

dragon (10, 45)

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• Can't understand something
• Think something is incorrect
• Want to improve something
• Want to contribute your own documentation

Then, this is the place to come to…

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