Why is this function returning null?

Hi,

I'm having trouble understanding why this code is not working.  Basically I load a figure into the scene and select it.

The script is then supposed to find a bone with the word "abdomen" in it's name (and then select the bone).  The function 'findBone()' appears to be working correctly,

but it keeps returning null instead of a bone.  I've been staring at it until I'm cross-eyed and I still can't see why it's doing this:

(function() {
	var title = "Select Child Nodes",
			node = null,
			skel = null;
	
	// Find a bone containing 'str' in it's name:
	function findBone(parent, str) {
		var len = parent.getNumNodeChildren(),
			child = null;
		
		for (var i=0; i<len; i++) {
			child = parent.getNodeChild(i);
			print("Checking: "+child.getName());
			
			if (child.getName().find(str) >= 0) {
				print(child.getName() + " found!");
				return child;
			}
		
			findBone(child, str);
		}
	}
	
	try {	
		node = Scene.getPrimarySelection();
		
		if (!node)
			throw new Error("Select a bone in a figure");
		
		if (node.inherits("DzSkeleton"))
			skel = node;
		else if (node.inherits("DzBone"))
			skel = node.getSkeleton();
		else
			throw new Error("Select a bone in a figure");		

		var abdomen = findBone(skel, "abdomen");
		if (abdomen)
		  abdomen.select(true);
		else
			print("Bone Not Found!");
	}
	catch(err) {
		MessageBox.critical(err.message + "\n(line: " + err.lineNumber + ")",
												title, "&OK" );
		return false;
	}
})()

 

Comments

  • Because you havea  recursive function. Although it returns the found bone on success, it is returning it to the previous calling function and that doesn't do anything with the result. Try storing the result of the return and then if it's valid return it to the next level up:

    	// Find a bone containing 'str' in it's name:
    	function findBone(parent, str) {
    		var len = parent.getNumNodeChildren(),
    			child = null,
    			result; // variable for tracking return values
    		
    		for (var i=0; i<len; i++) {
    			child = parent.getNodeChild(i);
    			print("Checking: "+child.getName());
    			
    			if (child.getName().find(str) >= 0) {
    				print(child.getName() + " found!");
    				return child;
    			}
    		
    			result = findBone(child, str); // keep the result of the next level down
    			if ( result ) {
    				return result; // pass a success back up the chain
    			}
    		}
    	}

     

  • Is the recursion really necessary?  It's made more complicated by the recursive call being inside a loop too.  Why not something like:

    		node = Scene.getPrimarySelection();
    		
    		arr = node.getNodeChildren(recurse=true);
    		
    		for (i=0; i<arr.length; i++){
    			if (arr[i].getName().find("abdomen") >=0){
    				print(node.getName() + ", " + arr[i].getName());
    			}
    		}

     

  • SimonJMSimonJM Posts: 5,279

    What recursion?  The findBone function is defined within anotehr function but it's closing brace is the one just above the try clause, so there's no recusrion that I can see - though admittedly I do not know the Daz scripting language!

  • barbultbarbult Posts: 12,167
    SimonJM said:

    What recursion?  The findBone function is defined within anotehr function but it's closing brace is the one just above the try clause, so there's no recusrion that I can see - though admittedly I do not know the Daz scripting language!

    Function findBone is calling findBone.

  • Stretch65Stretch65 Posts: 105

    I did it recursively just for the 'fun' of it.  Thanks Richard - it's been a while since I've tried simple recursion.

  • barbult said:
    SimonJM said:

    What recursion?  The findBone function is defined within anotehr function but it's closing brace is the one just above the try clause, so there's no recusrion that I can see - though admittedly I do not know the Daz scripting language!

    Function findBone is calling findBone.

    That's what I was referring to.  Should've been more specific.

  • Stretch65 said:

    I did it recursively just for the 'fun' of it.  

    Fair enough!  Gives me the heebie-jeebies, but each to their own.

  • SimonJMSimonJM Posts: 5,279
    barbult said:
    SimonJM said:

    What recursion?  The findBone function is defined within anotehr function but it's closing brace is the one just above the try clause, so there's no recusrion that I can see - though admittedly I do not know the Daz scripting language!

    Function findBone is calling findBone.

    Oh heck, so it is!

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