[Dan Ebberts]

If it’s the most recent expression, you probably just need to replace this:

if ((time-inPoint) < myReveal) 100 else 0

with this:

(time-inPoint) < myReveal ? 100 : 0

[Dan Ebberts]

I’d do the part below the function like this:

if (s < 0)
  ease(s,-10,0,hexToFloat(c1),hexToFloat(c2))
else
  ease(s,0,10,hexToFloat(c2),hexToFloat(c3));

[Dan Ebberts]

That’s because the Particle World Producer property expects its X coordinate (in this example) to be a percentage of comp width relative to the comp center. So the the second line of the expression calculates how far the null’s x position is from the x position of the comp center and divides that by the comp width to get a normalized value between -.5 and +.5.

[Dan Ebberts]

I’m not sure the eval() stuff you’re doing is necessary, but to your specific question–try this:

if (app.project.activeItem.layer(a).nullLayer) continue;

[Dan Ebberts]

Change the last line to this maybe?

[value[0],value[1],z.position.valueAtTime(sampleP)[2]]

[Dan Ebberts]

Depending on the type of layer, this might work:

[width,height]/2 + random([thisComp.width-width,thisComp.height-height])

[Dan Ebberts]

Something like this, maybe:

Mode = thisComp.layer("Control").effect("Mode (Dark/Night)")("Checkbox").value;
OnOff = thisComp.layer("Control").effect("OnOff")("Checkbox").value;
Opacity = thisComp.layer("Control").effect("Opacity")("Slider");
if (! OnOff){
  Mode ? Opacity : value;
}else{
  0;
}

[Dan Ebberts]

It’s controlling speed that’s tricky. This might help:

http://www.motionscript.com/articles/speed-control.html

[Dan Ebberts]

Unfortunately, all the characters in a text layer get the styling of the first character. You’re pretty much limited to what you can accomplish with animators (fill color, stroke width, etc.). Your second question though, could be done with a fill color animator and an expression selector that has an Amount expression like this:

txt = text.sourceText.value;
d = txt.indexOf(".");
d > -1 && textIndex > d+1 ? 100 : 0

[Dan Ebberts]

I’m guessing this is close to what you’re looking for:

var comp = app.project.activeItem;
if (comp instanceof CompItem){
	var selLay = comp.selectedLayers[0];
	var inOutlay = selLay.outPoint - selLay.inPoint;
	var newNull = comp.layers.addNull(inOutlay);
	newNull.moveBefore(selLay);
	newNull.startTime = selLay.inPoint;
	newNull.setParentWithJump(selLay);
};