Automatic import statements:

import java.lang.*;
import javax.vecmath.*;

import de.grogra.xl.lang.*;
import de.grogra.annotation.*;
import de.grogra.rgg.*;
import de.grogra.turtle.*;
import de.grogra.imp3d.objects.*;
import de.grogra.imp3d.shading.*;
import de.grogra.math.*;
import de.grogra.pf.data.*;

import de.grogra.graph.impl.Node;
import de.grogra.rgg.Attributes;

import static de.grogra.xl.util.Operators.*;
import static de.grogra.rgg.Library.*;
import static de.grogra.vecmath.VecmathOperators.*;
import static de.grogra.imp3d.shading.RGBAShader.*;
import static de.grogra.pf.ui.ChartPanel.*;
import static de.grogra.turtle.TurtleState.*;
import static de.grogra.xl.impl.base.Graph.*;

If you encounter simple names like Axiom or RED in one of the examples and wonder where they are declared, the possible locations are the imported packages and classes. But the simplest way to find the location is to use the index of the online documentation located at https://javadoc.grogra.de/index-all.html.

A class is declared implicitly, its name being the name of the source file, its superclass being de.grogra.rgg.RGG. The source code starting at the first declaration which is not a class or module declaration is considered as the body of the class. For example, if the file BinaryTree.rgg has the content

module X (float a);

const float A = 2;

public void derive () [
    Axiom ==> X(A);
    X(len) ==> F(len) [RU(30) X(len*0.7)] [RU(-30) X(len*0.7)];
]

then the actual class declaration is equivalent to

module X (float a);

public class BinaryTree extends de.grogra.rgg.RGG
{
    const float A = 2;

    public void derive () [
        Axiom ==> X(A);
        X(len) ==> F(len) [RU(30) X(len*0.7)] [RU(-30) X(len*0.7)];
    ]
}

double values can be used where float values are expected. E.g., the declaration

float x = 0.1;

is legal in the RGG dialect of XL, but illegal in Java, because 0.1 is a double literal. In Java, one would have to write 0.1f instead of 0.1.