package net.fortytwo.ripple.libs.math;
import net.fortytwo.flow.Sink;
import net.fortytwo.ripple.RippleException;
import net.fortytwo.ripple.model.ModelConnection;
import net.fortytwo.ripple.model.NumericValue;
import net.fortytwo.ripple.model.PrimitiveStackMapping;
import net.fortytwo.ripple.model.RippleList;
import net.fortytwo.ripple.model.StackMapping;
/**
* A primitive which consumes a numerator and divisor and produces their
* quotient. If the divisor is 0, no value is produced.
*
* @author Joshua Shinavier (http://fortytwo.net)
*/
public class Div extends PrimitiveStackMapping {
private static final String[] IDENTIFIERS = {
MathLibrary.NS_2013_03 + "div",
MathLibrary.NS_2008_08 + "div",
MathLibrary.NS_2007_08 + "div",
MathLibrary.NS_2007_05 + "div"};
public String[] getIdentifiers() {
return IDENTIFIERS;
}
public Div()
throws RippleException {
super();
}
public Parameter[] getParameters() {
return new Parameter[]{
new Parameter("x", null, true),
new Parameter("y", null, true)};
}
public String getComment() {
return "x y => y / x";
}
public void apply(final RippleList arg,
final Sink<RippleList> solutions,
final ModelConnection mc) throws RippleException {
RippleList stack = arg;
NumericValue a, b, result;
b = mc.toNumericValue(stack.getFirst());
stack = stack.getRest();
a = mc.toNumericValue(stack.getFirst());
stack = stack.getRest();
// Note: division by zero simply does not yield a result.
if (!b.isZero()) {
result = a.div(b);
solutions.put(
stack.push(result));
}
}
@Override
public StackMapping getInverse() throws RippleException {
return MathLibrary.getMulValue();
}
}