package org.simantics.r.scl.variable;

import org.rosuda.REngine.REXP;
import org.rosuda.REngine.REXPInteger;
import org.rosuda.REngine.REXPMismatchException;

public class RListLengthNode implements RVariableNode {

	RVariableNode parent;
	
	public RListLengthNode(RVariableNode parent) {
		this.parent = parent;
	}

	@Override
	public REXP getValue() {
		REXP parentValue = parent.getValue();
		if (parentValue == null)
			return null;
		
		try {
			return new REXPInteger(parentValue.length());
		} catch (REXPMismatchException e) {
			return null;
		}
	}

	@Override
	public String getName() {
		return "length";
	}

	@Override
	public RVariableNode getParent() {
		return parent;
	}
}