[ Feature request] : purge uninstalled .xbps files from /var/cache/xbps directory

[LinArcX]

Hi. and thank you for your great effort. I have a problem with xbps and it's that:
imagin you decide to install a package and after a while, you decide to delete it with:
sudo xbps-install -S foo.
Actually it doesn't delete .xbps files from: /var/cache/xbps and after some times if you install-uninstall some packages, your /var/cache/xbps directory will occupied with .xbps files that no longer related to any installed package on your machine.
I know we can go to that directory and start deleting packages one by one. it's easy for packages with low dependencies but imagine you install plasma-desktop or gnome with more than 150 dependencies.
How you can find them? absolutely it's time consuming and an error-prone process.
So i think there should be some script to do it for us automatically. I also said this problem here:
void-linux/xbps#156 (comment)
And @pullmoll offer me a script in last part. I tried it and it works. But i think it can be improved and then merged to your repo.

[leahneukirchen]

Doesn't xbps-remove -O do that?

[LinArcX]

@leahneukirchen No.

This is not a bug. The option -O removes orphaned packages from the cache while the xfce4*.xbps and its *.sig files in your cache are not orphans

void-linux/xbps#156 (comment)

Edit: I start to manipulate that script and add some stuffs to it. Can i send you as PR?