Karel++ Info

There is a book about Karel++. Several of the chapters are reproduced here (you can also get the Mac version from this site).

Information about Karel (from Bergin, et. al)

• Primitive instructions for ur_Robot objects

  class ur_Robot 
  {
     void move();       // robot moves forward one block
  
     void turnOff();    // robot turns itself off
  
     void turnLeft();   // robot pivots in place 90 degrees
  
     void pickBeeper(); // robot picks up beep and puts it into a bag
  
     void putBeeper();  // robot takes beeper out of bag and places on corner
  }
  

• Conditions for Robot objects

  class Robot: ur_Robot 
  {
     Boolean frontIsClear();
  
     Boolean nextToABeeper();
  
     Boolean nextToARobot();
   
     Boolean facingNorth();
  
     Boolean facingSouth();
  
     Boolean facingEast();
  
     Boolean facingWest();
  
     Boolean anyBeepersInBeeperBag();
  }
  

• Conditional instructions

  • if ( <test> )
    {
        <instruction>
        <instruction>
        ...
        <instruction>
    }
    

  • if ( <test> )
    {
        <instruction>
        <instruction>
        ...
        <instruction>
    }
    else
    {
        <instruction>
        <instruction>
        ...
        <instruction>
    }
    

• Repetition Instructions

  • while ( <test> )
    {
        <instruction>
        <instruction>
        ...
        <instruction>
    }
    

  • loop ( <positiveNumber> )
    {
        <instruction>
        <instruction>
        ...
        <instruction>
    }
    

• Basic program form:

  task
  {
      <robotInitialization>
      ...
      <robotInitialization>
      <instruction>
      <instruction>
      ...
      <instruction>
  }
  

• Robot initialization

  ur_Robot <name>(<street>,<avenue>,<direction>,<numBeepers>);
  
  Robot <name>(<street>,<avenue>,<direction>,<numBeepers>);
  

• You must shut-off the robot at the end of the program. Error shut-offs occur after some instructions are executed.
  • A robot executes a move instruction when a wall blocks the path to the immediate next corner.

  • A robot executes a pickBeeper when it is on a corner with no beepers.

  • A robot executes a putBeeper when it has no beepers in its bag.