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Why is this function returning null?

Stretch65Stretch65 Posts: 157
in Daz Script Developer Discussion

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

  • Richard HaseltineRichard Haseltine Posts: 96,718

    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			}		}	}

     

  • andya_b341b7c5f5andya_b341b7c5f5 Posts: 694

    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: 5,945

    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: 23,133
    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: 157

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

  • andya_b341b7c5f5andya_b341b7c5f5 Posts: 694
    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.

  • andya_b341b7c5f5andya_b341b7c5f5 Posts: 694
    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: 5,945
    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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