package net.fortytwo.ripple.libs.data;
import net.fortytwo.flow.Sink;
import net.fortytwo.ripple.RippleException;
import net.fortytwo.ripple.libs.graph.GraphLibrary;
import net.fortytwo.ripple.model.ModelConnection;
import net.fortytwo.ripple.model.PrimitiveStackMapping;
import net.fortytwo.ripple.model.RippleList;
import net.fortytwo.ripple.model.RippleValue;
/**
* A primitive which consumes two resources and produces a comparison value
* according to their data type.
*
* @author Joshua Shinavier (http://fortytwo.net)
*/
public class Compare extends PrimitiveStackMapping {
public String[] getIdentifiers() {
return new String[]{
DataLibrary.NS_2013_03 + "compare",
GraphLibrary.NS_2008_08 + "compare",
GraphLibrary.NS_2007_08 + "compare",
GraphLibrary.NS_2007_05 + "compare"};
}
public Compare()
throws RippleException {
super();
}
public Parameter[] getParameters() {
return new Parameter[]{
new Parameter("x", null, true),
new Parameter("x", null, true)};
}
public String getComment() {
return "x y => i -- where i is -1 if x < y, 0 if x = y, and 1 if x > y";
}
public void apply(final RippleList arg,
final Sink<RippleList> solutions,
final ModelConnection mc) throws RippleException {
RippleList stack = arg;
RippleValue y, x;
y = stack.getFirst();
stack = stack.getRest();
x = stack.getFirst();
stack = stack.getRest();
int result = mc.getComparator().compare(x, y);
// Constrain the result to three possible values.
result = (result < 0) ? -1 : (result > 0) ? 1 : 0;
solutions.put(stack.push(mc.valueOf(result)));
}
}