Antlr4 Turtle

This is a very basic implementation of the [Logo Language](https://en.wikipedia.org/wiki/Logo_(programming_language) using the Antlr4 parser generator. The Logo programs are parsed based on the Logo Grammar and visualized in a JavaFX UI

Grammar

The grammar and this program's capabilities are not a full Logo Language implementation. The basic expressions that are supported are:

• forward ${points}: Move forward x points
• back ${points}: Move backward x points
• right ${degrees}: Turn right x degrees
• left ${degrees}: Turn left x degrees
• set ${x},${y}: Sets the turtle on point (x,y)
• clearscreen: Clear the canvas
• penUp: The pen is up hence cannot draw to the canvas
• penDown: The pen is down ready to draw to the canvas
• resetAngle: Resets the turtle's direction angle to 0 degrees which is effectively facing east

Example

An example of a simple Hello World logo program can be found at HelloWorld.logo

Running The UI

The UI can be launched by invoking TurtleRunner and it will automatically load the example file. Running the demo program will produce an animation like the below:

UI Features

• User can type a logo program in the text area
• User can load a logo program from File->Open...
• The slider determines the drawing animation speed