Welcome to Reeborg’s World’s documentation!

This is a model of Reeborg made by a student in New Jersey (USA) who learned Python with RUR-PLE, an older version of Reeborg’s World that has been available as a desktop program since 2004.

Photo courtesy of A. Judkis.

Reeborg’s World is an adaptation of Richard Pattis’s Karel the robot. It supports three programming languages (Python, Javascript and CoffeeScript). However, the focus of this documentation is on Python which is my favourite programming language and, I believe, the ideal one to use for teaching programming concepts.

Reeborg’s World is free: free to use, free to copy (and put on a school’s website), and does not require any registration or login. Unlike some other existing code learning website, it does not force learners to follow a pre-defined path; educators are free to create their own learning material and make use of Reeborg’s World.

Task Driven Learning

Reeborg’s World is designed for Task Driven Learning: students are given tasks that Reeborg has to complete, and they must write programs instructing Reeborg how to do so.

Tasks include having Reeborg move objects, build walls, or go to a particular location. Objects in Reeborg’s World are colourful; the places they be must moved to by Reeborg are indicated by having a picture of the object in shades of grey.

• 1. Who is Reeborg?
• 2. Quick tour of Reeborg’s World
  • 2.1. Running programs
  • 2.2. Receiving feedback
  • 2.3. Creating new worlds and tasks
• 3. Information for students
• 4. Information for educators
  • 4.1. In the beginning ...
  • 4.2. Advanced tasks
  • 4.3. More information
• 5. Basic commands
  • 5.1. Movement
    • 5.1.1. move()
    • 5.1.2. turn_left()
  • 5.2. Handling objects
    • 5.2.1. take()
    • 5.2.2. put()
  • 5.3. Getting information about the world around
    • 5.3.1. is_facing_north()
    • 5.3.2. at_goal()
    • 5.3.3. front_is_clear()
    • 5.3.4. right_is_clear()
    • 5.3.5. object_here()
    • 5.3.6. carries_object()
  • 5.4. Interruptions
    • 5.4.1. pause()
    • 5.4.2. done()
    • 5.4.3. think()
  • 5.5. Changing the world
    • 5.5.1. build_wall()
• 6. Objects, background images, etc.
  • 6.1. Basic objects
  • 6.2. Background tiles
  • 6.3. Special objects
  • 6.4. Goals
• 7. A quick Python introduction: part 1
  • 7.1. What is a Python program?
  • 7.2. What is a function?
  • 7.3. What is a valid name (for a function ... or other “things”)?
  • 7.4. What is the meaning of the symbol #?
  • 7.5. How do I define a function? (Python keyword def)
  • 7.6. How do we call a function?
  • 7.7. Are there other ways to name ... things ?
  • 7.8. Repeating instructions (Python keywords for, in)
  • 7.9. Python keywords: if, True, False, and not
  • 7.10. Python keyword: while
• 8. A quick Python introduction: part 2
  • 8.1. Keywords and
  • 8.2. Keywords elif and else
  • 8.3. Keyword or
  • 8.4. Keywords break and continue
  • 8.5. Summary of logical keywords
  • 8.6. Summary of control flow keywords
  • 8.7. One more keyword: pass
• 9. A quick Python introduction: part 3, Using the library
  • 9.1. Other notation: import without from
  • 9.2. Keyword as
  • 9.3. Importing everything
• 10. A quick Python introduction: part 4, Exceptions
  • 10.1. The keyword raise
  • 10.2. The keywords try, except, and finally
• 11. More advanced programming
  • 11.1. Worlds with multiple types of objects
  • 11.2. Other functions with arguments
  • 11.3. Communications from Reeborg
  • 11.4. Working with lists
  • 11.5. Return statement
• 12. Object-Oriented Programming
  • 12.1. Object-Oriented Programming
  • 12.2. Multiple robots
  • 12.3. Better robots
  • 12.4. Four important ingredients for designing a better robot
  • 12.5. Fixing the leak
  • 12.6. Facing south
  • 12.7. Exploring the code
  • 12.8. Javascript !??
  • 12.9. About the single move()
• 13. Sokoban
  • 13.1. Sokoban and Reeborg’s World
  • 13.2. More challenges
  • 13.3. Why sokoban?
  • 13.4. Sokoban for advanced students
• 14. Custom worlds: making them available
  • 14.1. Default worlds
  • 14.2. Creating worlds
  • 14.3. Using Permalinks
  • 14.4. Using the World() function
  • 14.5. Creating custom menus
• 15. Advanced features
  • 15.1. Simple task
  • 15.2. Different traces: style
  • 15.3. Different traces: color
  • 15.4. Different robot models
  • 15.5. Random worlds
  • 15.6. Adding code to be run in addition to user’s program
  • 15.7. Replacing the default robot
  • 15.8. Enhanced goals
    • 15.8.1. Actual code for verify()
    • 15.8.2. Actual code for confirmer()
  • 15.9. Easy collaboration with TogetherJS
  • 15.10. Using Python’s standard library
  • 15.11. Possibility to write programs using different languages
  • 15.12. Stepping back and forth through program execution
  • 15.13. Easy support for multiple human languages
  • 15.14. Possibility to integrate within a Learning Management System
  • 15.15. Changing the User Interface
• 16. World contributed by users
• 17. Information for translators
• 18. Information for artists
• 19. Information for developers
• 20. Current weaknesses
  • 20.1. Inadequate support for input()
  • 20.2. Occasional problems with code highlighting
  • 20.3. No gamification
  • 20.4. Not trivially easy to create a copy on a school’s website
  • 20.5. Feedback for programming errors could be improved
• 21. Comparison with other implementations
  • 21.1. First, Reeborg’s World
  • 21.2. Karel the robot
  • 21.3. Karel++
  • 21.4. Monty Karel
  • 21.5. Karel J. Robot
  • 21.6. Guido van Robot
  • 21.7. Code Combat
• 22. Graphical canvas
• 23. Mazes