type_hierarchy.py

"""
Script with :func:`build_hierarchy` function as an entry point. 

Specify the class and get its inheritance hierarchy. 

See also :mod:`inspect.getclasstree` as an alternative implementation.

There is also a way to convert hierarchy to the dot-language graph - :func:`node_to_dot_graph`
"""

import itertools
from collections import namedtuple


class Node(namedtuple('Node', 'value children')):
  """Node in the hierarchy"""
  
  def __repr__(self):
    if not self.children:
      return self.value
    return super(Node, self).__repr__()

  
def build_hierarchy(cls):
  """Build inheritance hierarchy of the specified class
  
  types.ClassType -> Node
  """
  return Node(
    value=cls.__name__,
    children=[
      build_hierarchy(sub_cls) 
      for sub_cls in cls.__subclasses__()
    ]
  )


def node_to_dot(node):
  """Convert node to the statement in the dot-language.
  
  Node -> str
  """
  return "\n".join(
    itertools.chain(
      (
        '{} -> {};'.format(node.value, child.value) 
        for child in node.children
      ), 
      (node_to_dot(child) for child in node.children)
    ))


def node_to_dot_graph(node):
  """Convert recursively node to the graph in the dot-language.
  
  Node -> str
  """
  return """
  digraph {name} {{
    {nodes}
  }}
  """.format(
    name=node.value,
    nodes=node_to_dot(node)
  )


if __name__ == '__main__':
  hierarchy = build_hierarchy(Exception)

  with open('~/Temp/exception.dot', 'w+') as fd:
    fd.write(node_to_dot_graph(hierarchy))