cod is a source "package manager" based on makepkg, pacman, and asp. It's
really just a shell script that fetches sources from the Arch Build System and
keeps them organized for you. What makes it interesting is that it also
maintains a symlink farm based on the binaries that pacman knows about from
the installed packages. All of them link to codstub, an even smaller shell
script which recognizes which binary you're trying to run and runs the build
step of the package's PKGBUILD on the fly before launching the binary.
This may have buried the lede a bit, so TL;DR: cod allows you to edit your tools in real time. You never have to think about which build system they use, or where to put the binaries.
This is made tolerable by the fact that modern build systems tend to be aware of what has changed since the last build. If the source is the same, the overhead added by cod is equal to the time it takes the build system of the package to start up and determine there's nothing to do. This of course varies quite a bit, but there's nothing we can do about that.
Set your CODPATH (it defaults to /opt/cod), and make sure you can write to it. Add $CODPATH/bin to your $PATH to make the experience seamless, but this is technically optional.
codinstall <package>. That's it. When you run the program you installed for
the first time it will be compiled from scratch, so it will likely be quite
slow. Subsequent runs should be nearly the same as running the binary directly.
This is a toy, but it does what it says on the tin. It was written on a whim to play with the idea. Whether it's actually useful is debatable.
It currently assumes that your pacman file database is up to date, in order
to avoid ever needing to escalate privileges. If it breaks, try pacman -Fy.
cod currently only works on binaries. While you can install the sources for libraries, it doesn't know to use this copy of the library to build other packages that depend on it. There's nothing preventing this from being added, though! It would need to do some ld magic when executing the binaries to deal with dynamic linking as well…
It would also be smart to add an option to immediately build installed packages, instead of waiting to do it the first time you run one of the binaries.