module Graph

parameter　root　Object

The root object to start from.

parameter　depth　Integer

Maximum depth to traverse (nil for unlimited).

parameter　seen　Set

Set of already seen objects (for internal use).

parameter　ignore　Array

Array of types to ignore during traversal.

parameter　parent　Node | Nil

The parent node (for internal use).

returns　Node

The root node with children populated.

def self.for(root, depth: nil, seen: Set.new.compare_by_identity, ignore: IGNORE, parent: nil)
	if depth && depth <= 0
		# Compute shallow usage for this object and it's children:
		usage = Usage.of(root, seen: seen, ignore: ignore)
		return Node.new(root, usage, parent)
	end
	
	# Compute shallow usage for just this object:
	usage = Usage.new(ObjectSpace.memsize_of(root), 1)
	
	# Create the node:
	node = Node.new(root, usage, parent)
	
	# Mark this object as seen:
	seen.add(root)
	
	# Traverse children:
	ObjectSpace.reachable_objects_from(root)&.each do |reachable_object|
		# Skip ignored types:
		next if ignore.any?{|type| reachable_object.is_a?(type)}
		
		# Skip internal objects:
		next if reachable_object.is_a?(ObjectSpace::InternalObjectWrapper)
		
		# Skip already seen objects:
		next if seen.include?(reachable_object)
		
		# Recursively build child node:
		node.add(self.for(reachable_object, depth: depth ? depth - 1 : nil, seen: seen, ignore: ignore, parent: node))
	end
	
	return node
end