Loose coupling is a design property in which software components interact without relying heavily on one another’s internal details. It lets different areas change with less risk of breaking surrounding code. section 1.4.1 section 10.1.3
Think of coupling as a flexible mesh between pieces of code. A tightly woven section forces neighboring pieces to move together; a looser section permits change. Coupling is a continuum, not an all-or-nothing condition. section 10.1.1
Reduce coupling by making responsibilities and interactions easier to change:
- Separate concerns so presentation, business logic, and persistence can evolve independently. section 10.3
- Encapsulate data and behavior, then expose a focused shared abstraction instead of requiring callers to know implementation details. section 10.1.3 section 10.5
- Prefer configuration data for simple mappings when conditional logic would entangle choices with outcomes. section 7.1.2
- Recognize direct dependencies that would force shotgun surgery when adding behavior or replacing an implementation. section 7.1.3
Expose one message instead of several implementation steps
A caller that cleans a query by invoking remove_spaces, remove_quotes, and normalize must know the cleaning sequence. A focused clean_query function hides those details and gives callers one stable interaction: clean_query(query). The same principle appears in Bark, where menu options trigger commands through a shared execute abstraction rather than depending on each command’s implementation. section 10.1.3 section 10.3
Listing 10.6. Simplifying a shared interface
import re
def _remove_spaces(query): #1
query = query.strip()
query = re.sub(r'\s+', ' ', query)
return query
def _normalize(query):
query = query.casefold()
return query
def _remove_quotes(query):
query = re.sub(r'"', '', query)
return query
def clean_query(query): #2
query = _remove_spaces(query)
query = _remove_quotes(query)
query = _normalize(query)
return query
if __name__ == '__main__':
search_query = input('Enter your search query: ')
search_query = clean_query(search_query) #3
print(f'Running a search for "{search_query}"')
Inspect the compact Python example that wraps several query transformations behind the clean_query interface. section 10.1.3
