JessieCode language reference

Datatypes

• Boolean, true or false (case insensitive, tRuE is a valid boolean constant).

• Strings are defined using single quote marks. Quote marks inside a string have to be escaped with a backslash.

• Number, corresponds to the JavaScript number datatype.

• Objects, can be created only via object literal notation << >> and the predefined element functions (see below). To access properties and methods the operator is used. Example:

obj = <<
  property: 'string',
  prop: 42,
  method: function (x) {
      return x*x;
  }
>>;
sixteen = obj.method(4);

• Functions are declared with the function operator

f = function (a, b, c) {
  return a+b+c;
};

Comments

Only one line comments with // being the first non-whitespace characters are supported right now.

Operators

Logical operators

Arithmetic operators

Assignment operators

Comparison operators

String operators

Member operators

Control structures

The control structures are exactly the same as in JavaScript.

If

if (<expression) {
  <Stmt>
} else if (<expression>) {
  <Stmt>
} else {
  <Stmt>
}

While loop

while (<expression>) {
  <Stmt>
}

Do loop

do {
  <Stmt>
} while (<expression>);

For loop

for (<assignment>; <expression>; <assignment>) {
  <Stmt>
}

Predefined constants

Predefined functions

Math functions

$board methods

Element functions

Every element known to the loaded JSXGraph version is available inside Jessie by its element type, e.g. points can be created by calling point()

A = point(1, 2);

The given parameters correspond to the parents array of the JXG.Board.create() method. Attributes are given after the function call itself in an object:

A = point(1, 2) << strokeColor: 'red', face: '[]', size: 7, fillColor: 'black' >>;

For a possibly incomplete list including documentation, see the JSXGraph docs; For a complete list see the Element reference section below.

Accessing elements

Variable assignment

A = point(1, 2);
A.strokeColor = '#123456';

$

point(1, 2) << id: 'foo', name: 'bar' >>;
$('foo').strokeColor = '#654321';

Id

point(1, 2) << id: 'foo', name: 'bar' >>;
foo.strokeColor = '#f00f00';

This is possible only if foo is not used as a variable. This won't work:

foo = 1;
(function () {
  point(1, 2) << id: 'foo' >>;
  return foo.X();
})();

Name

point(1, 2) << id: 'foo', name: 'bar' >>;
bar.strokeColor = '#541541';

This is possible only if there is not a variable called bar in the current or any higher scope. See Id above for an example.

Element reference

https://jsxgraph.uni-bayreuth.de/docs/

Attributes

Attributes are set like object properties

A.size = 10;
A.face = '[]';

See the JSXGraph docs for available attributes. Texts and Points have two special attributes X and Y to set their coordinates.

Subelements

Subelements like labels for points or the baseline in sliders or the dot indicating an angle element is a right angle can be accessed like properties

A.label.strokecolor = 'red';

The names used to access subelements correspond to their names used to set their attributes inboard.create.

Methods

Not all methods of an element class are accessible in Jessie. Currently these methods are available:

• all elements
  • setLabelText
• point
  • move
  • glide
  • free
  • X
  • Y
• glider
  • all from point
  • setPosition
• text
  • setText
  • free
  • move
• slider
  • Value
• angle
  • Value