Python Immutable Enumerations Using Duck Punching (Python)

2012-10-18T19:41:22-07:00

Python recipe 578294 by Josh Friend (duckpunching, enum, enumeration, monkeypatching, python).

Here's a fun method of creating enumerations in Python using dynamic class creation and duck-punching (monkey-patching). It works by creating a class called enum using the type metaclass. Duck-punching is then used to add properties to the class. the fget method of the property returns the enum value, but the fset and fdel methods throw exceptions, keeping the enumeration immutable. You can have enum values assigned automatically in sequence, assign them yourself, or have a mix of both.

Dynamically modifying class attributes at runtime (Python)

2011-03-31T20:07:18-07:00

Python recipe 577628 by Nabil Stendardo (class, modification, monkeypatching, open).

However considered bad programming, Ruby/JavaScript-like open classes (i.e. classes which can be modified at runtime) actually can be a programming pattern when developing plug-in architectures. And, guess what, Python has that functionality too. This code allows to add attributes (typically methods) to classes, even when already instantiated.

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Python Immutable Enumerations Using Duck Punching (Python)

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