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This page describes the planning of Pyjama Editor and Shell. The Pyjama IDE is a cross-platform environment for learning about computing. This is part of the Pyjama Project.


Getting Source Code

For those with write permissions to the SVN Bryn Mawr College source code repository:

svn co Pyjama

You can browse the source code here:

You will also need:

  • mono
  • gtk (and libgtk2.0-cil-dev, for package-config files)


You do not need to make anything. All of the libraries that you need come pre-built. But, if you want to know, this section describes what you need to do.

You will need petite scheme to make Pyjama Scheme from scratch.

To build everything, run "make" in the root:

cd Pyjama

That will build platform independent modules/Myro.dll, modules/Graphics.dll, and languages/Scheme.dll.

To run code:

cd Pyjama


There are 5 directories in the Pyjama folder:

  1. bin - contains the startup exe and dll files
    1. bin/Lib - contains the standard Python libraries
  2. languages - contains the language definition files for Python, Ruby, Scheme, and Dinah
  3. modules - Cross-language modules that can be used by all Pyjama languages
  4. examples - sample code, broken down by language
  5. src - the code to run the Pyjama Project

Pyjama is written in IronPython, using the Gtk# graphical toolkit. The Python files for the Pyjama Project are in Pyjama/src/*.py. They are:

  • - the Chat window
  • - base classes for Document interface
  • - the Editor Window
  • - base classes for the Engine interface
  • - setup and startup code
  • - code to read DLL data
  • - the Shell Window
  • - utility functions and classes (chat, windows, functions, etc.)
  • - base class for Shell, Editor, and Chat

Pyjama is an editor and executor of code from a Language. Languages are defined in Pyjama/languages and define two items: editor document, and an executor engine. Pyjama has 4 languages, in various states of completeness:

  1. Python (finished)
  2. Ruby (nearly finished)
  3. Scheme (somewhat working)
  4. Dinah (drag and drop language, just started)
  5. Sympl (experimental Lisp-like language written in Python for the DLR)
  6. C# (experimental, no functions, no classes, no DLR)

A Language file in Pyjama/languages/*.py defines the editing document, and the shell executor API. Documents can do things like open, save, and display data for editing. Engines can do things like execute, execute_file, and parse files. Engines also allow for the languages to share data and functionality.


See NOTES in the Pyjama download (package or svn).

Screen Shots


For more, see PyjamaScreenShots

Python and Ruby

Pyjama allows you to easily jump back and forth between languages. Enter this code in the command box:

def fib(n):
    if n <= 2: return 1
    return fib(n - 1) + fib(n - 2)

Make sure the bottom status line has Python checked, and press the Run! button (or simply hit <enter> when in the command box).

Now, enter this code in the command box (make sure to set bottom status line has Ruby checked).

class Hello_world
  def greet
    puts "Hello World"
hw =

Cross-language Access

In this example, you'll see that you can access code and variables defined in other languages.

Enter the following in the Interactive Command Box:

class PythonClass:
     def hello(self, value):
         print "Python says hello to", value

This defines a PythonClass. To test it out, enter the following in the command box:

pc = PythonClass()

In the Output Box, you'll of course see:

Python says hello to Python

Now, switch to Ruby mode (bottom line status bar, select Ruby) and enter this in the command box:

pc = python_class().new
pc.hello "Ruby"

This uses the PythonClass (now called python_class). In Ruby, you can create an object by placing the .new after it. You call the method .hello by placing the arguments after the method name (parens are not needed in Ruby).

You will see in the output box:

Python says hello to Ruby

which is Python code running inside Ruby!

While in Ruby Mode, enter:

class Ruby_class
   def hello caller
     puts "Ruby says hello to #{caller}"

To see that work, try:

rc =
rc.hello "Ruby"

and you'll of course see:

Ruby says hello to Ruby

Finally, switch back to Python Mode, and enter:

import Ruby_class
rc = Ruby_class()

and you'll see:

Ruby says hello to Python

which is Ruby code running in Python!

Interacting with .NET

The languages of Pyjama can also interact with .NET/Mono. If you are already familiar with .NET/Mono programs (such as those written in C# or Visual Basic) then you will recognize some of these idioms and names.

As a simple example, let's use the interactive abilities to directly interact with some Windows Forms. In order to do this in Pyjama, will turn the threaded ability off, so as to talk to the GUI in the same thread as Pyjama is running in. Let's create a window (called a Form in .NET parlance):

# file:
import clr
from System.Windows.Forms import *
import pyjama
pyjama.Threaded = False
win = Form()

Importing the special module named clr is the gateway to interacting with the underlying .NET/Mono subsystem. From the clr module, you can add a reference to any Dynamic Link Library (DLL) so that you can access library functions and objects. In this example, we add a reference to the System.Windows.Forms DLL which contains a library of Graphical User Interface (GUI) objects. We then can create a Form, save it in a variable named win, and call the form's Show() method.

If you'd like to give the window a name, enter this in Pyjama's interactive command box:

win.Text = "This is the Window Title"

These windows will go away when you close Pyjama, or you can close them manually.

Developing a Language for the DLR in the DLR

Python and Ruby are defined to interact as above by taking advantage of the Dynamic Language Runtime (DLR). To further show this off, here is an example of defining a new language, much like Lisp, called SymPL written in Python using the tools of the DLR:

  1. - the lexer
  2. - the parser
  3. - expression tree generators
  4. - runtime helpers (e.g., lookup, import)
  5. - the Read Eval Print Loop

Some sample SymPL programs:

  1. test.sympl - function tests
  2. ops.sympl - operator tests
  3. lists.sympl - list tests

Writing Fast Module Code Once

Perhaps the nicest aspect of the DLR is that you can develop code (in CSharp, for example) that is "compiled" and used directly. Such can be imported and used by any language in the DLR suite as if it were written in that language. For example, consider this simple example:

// file: Testing.cs
public class Point {
  private int _x;
  private int _y;
  public Point(int x, int y) {
	_x = x;
	_y = y;
  public int x {
	get { return _x; }
	set { _x = value; }
  public int y {
	get { return _y; }
	set { _y = value; }
  public string __repr__() {
	return "<Point at (" + _x + "," + _y +")>";

This can be compiled in Mono:

gmcs Testing.cs -target:library

or put into a Project in Visual Studio, and compiled into a library.

You should then put the resulting Testing.dll somewhere will Pyjama can find it (either put in the same directory with the pyjama.exe, or put it in a directory and add the path of the directory to Python's sys.path):

import sys

Finally, you can use it in Pyjama:

>>> import clr
>>> clr.AddReference("Testing")
>>> import Point
>>> Point
<type 'Point'>
>>> p = Point(1,2)
>>> p
<Point at (1,2)>
>>> p.x
>>> p.x = 9
>>> p
<Point at (9,2)>

Creating Interactive Programs and Graphics for the Web

Once you have a working program in Pyjama, you can save the program to run on the Web in a manner very much like Flash applications. The resulting program can run in a browser using Silverlight/Moonlight. Example coming soon!


If you have any trouble, find bugs, or want to make a feature request, please do that at: