Lesson 42 of 55
9 mins readPython Multiple Inheritance & Method Search
In Plain English
Multiple inheritance is implemented by setting `__index` to a function that searches across multiple parent class tables sequentially until the requested method is found.
Deep Dive: How It Works
__index as Search Function: `function(table, key)` iterates parent classes.
Mixin Pattern: Composing behavior from multiple source tables into a new class.
Search Order: Determines method resolution order (MRO) when names collide.
Core Rules to Remember
Custom __index Search: Searches an array of parent classes dynamically.
Composition & Mixins: Combines capabilities from multiple classes (e.g. CanFly and CanSwim).
Live Interactive Example
Hit Run Code to see it liveMultiple Inheritance via __index Search Function
Python 3.12
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Output Console
Click "Run Code" to view the rendered output.
How it works: __index searched Walker first, then Flyer, finding both methods.
Your Turn: Micro Challenge
No pressure! Edit the starter code below and test your solution with instant feedback.
Micro Exercise
Combine Two Mixins
- Create `local Loggable = { log = function(self, msg) return "[LOG] " .. msg end }`.
- Create `local User = { name = "Alice" }`. Set metatable `{ __index = Loggable }`.
- Print(User:log("User created")).
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Sandbox Output
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