Exercises in Programming Style

Chapter 14

Hollywood

14.1 Constraints

• Larger problem is decomposed into entities using some form of abstraction (objects, modules or similar).
• The entities are never called on directly for actions.
• The entities provide interfaces for other entities to be able to register callbacks.
• At certain points of the computation, the entities call on the other entities that have registered for callbacks.

14.2 A Program in this Style

  1 #!/usr/bin/env python
  2 import sys, re, operator, string
  3
  4 #
  5 # The "I'll call you back" Word Frequency Framework
  6 #
  7 class WordFrequencyFramework:
  8 _load_event_handlers = []
  9 _dowork_event_handlers = []
 10 _end_event_handlers ...