How To Sort Based On Dependencies?

I have an class that has a list of 'dependencies' pointing to other classes of the same base type. class Foo(Base): dependencies = [] class Bar(Base): dependencies = [Foo]

Solution 1:

It's called a topological sort.

def sort_deps(objs):
    queue = [objs with no dependencies]
    while queue:
        obj = queue.pop()
        yield obj
        for obj in objs:
            if dependencies are now satisfied:
                queue.append(obj)
    if not all dependencies are satisfied:
        error
    return result

Solution 2:

I had a similar question just last week - wish I'd know about Stack Overflow then! I hunted around a bit until I realized that I had a DAG (Directed Acyclic Graph since my dependencies couldn't be recursive or circular). Then I found a few references for algorithms to sort them. I used a depth-first traversal to get to the leaf nodes and add them to sorted list first.

Here's a page that I found useful:

Directed Acyclic Graphs