Summary Karel Language

Summary of Karel's Programming Language

Primitives

Conditions (tests)

Conditional statements

Repetition statements (loops)

Creating tasks, classes, and instructions

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>);

Creating New Classes and Instructions

class <new-class-name>: <old-class-name>
    {
    <list-of-instructions>
    }

    <definition-of-new-instructions>

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.