During a program's initialization process it's really common for some singletons to be dependent on other singletons. For example, Foo needs a handle to data in Bar before Foo can be initialized. For really large software projects with many maintainers, keeping this initialization process straight can get to be a headache. That's where the init_tree comes in.
At program startup you add all of your singletons to the tree, and then call
init() on the tree. It will resolve all of your data dependencies at runtime.
It does so by utilizing a trait implemented on all of your singletons, Init.
Init is implemented automatically for singletons with Default implemented.
The Init trait provides a list of dependencies, and a function to initialize the
structure with those dependencies. Additionally, a macro impl_init! is provided
in order to make implementing Init easy to do.
This crate should be usable as is, however it needs better documentation and more unit testing.