PrePro

Student project at the DHBW Karlsruhe

The Language is designed to simply calculations with time series. To do so, each variable (except of constants) is a time-series. For example a variable with the type vec3 is a time-series of Vectors with the length 3. A PrePro-programm is written in a specific Domain Specific Language in textual form and is run by an Interpreter. The Interpreter takes and returns an PreProDataSet, which stores a set of variables (time-series).

Contents of this repository

Folder	Contents
PrePro	The source code of the interpreter.
PrePro-Netbeans-Plugin	A plugin for the Netbeans IDE supporting syntax highliting and syntax error detection.
Elaboration	The document written for the university. It is written in german.

The "Hello world" PrePro program

Simplified PrePro syntax

import vec3 p1, p2;

vec3 result = p1 + p2;

export result;

It uses the variables p1 and p2 from the given PreProDataSet and calculates a resulting Vector3. Remind: All the variables are time-series, there is no need for a loop. The Interpreter will return a PreProDataSet containing the result.

Buildin functions and operators

User defined Functions

function main() {
	import vec3 p1, vec3 p2, vec3 p3;

	vec3 x = calculateDifference(p1, p2);
	vec3 s = calculateDifference(p1, p3);
	vec3 y = s X x;
	vec3 z = y X x;

	export x, y, z;
}

function calculateDifference(vec3 p1, vec3 p2) returns vec3 {
	return p2 - p1;
}

The operation “X” is a cross product. Note, that PrePro currently doesn't support overloading of functions.

Constants

Constants can be defined and set into the SymbolTable:

PreProProgram program = new PreProProgram("foo.prepro");
SymbolTable symbolTable = new SymbolTable();
symbolTable.setValue("pi", new Constant(Math.PI);
PreProDataSet result = program.execute(dataSet, symbolTable);
double pi = result.getVariable()("pi").getDouble(0,0);

Limitations: Only double constants available?

Run the PrePro-program

To run the PrePro code you must provide a PreProDataSet. The following JAVA code creates a PreProDataSet and calls the PrePro-code.

INDArray p1 = Nd4j.create(new double[]{42, 0, 0, 1, 0, 0, 5, 0, 0, 6, 0, 0, 1, 2, 3}, new int[]{4, 3});
INDArray p2 = Nd4j.create(new double[]{43, 0, 0, 44662, 0, 0, 6, 0, 0, 7, 0, 0}, new int[]{4, 3});
INDArray p3 = Nd4j.create(new double[]{42, 0, 1, 1, 0, 1, 5, 0, 1, 6, 0, 1}, new int[]{4, 3});

PreProDataSet preProDataSet = new DefaultPreProDataSet(
        Arrays.asList(p1, p2, p3),
        Arrays.asList("p1", "p2", "p3")
);

PreProProgram program = new PreProProgram("src/test/tests/arithmetic/testCrossProduct.prepro");
PreProDataSet result = program.execute(preProDataSet);

System.out.println("Calculated x:\n" + result.getVariable("x"));
System.out.println("Calculated y:\n" + result.getVariable("y"));
System.out.println("Calculated z:\n" + result.getVariable("z"));