Lesson 29 of 55
10 mins readPython Algebraic Data Types (data ADT)
In Plain English
Algebraic Data Types (ADTs) allow defining rich custom domain types. Combine alternative variants (sum types with |) and composite fields (product types).
Deep Dive: How It Works
Sum Types (Enums/Variants): data TrafficLight = Red | Yellow | Green deriving (Show, Eq).
Product Types with Arguments: data Shape = Circle Double | Rectangle Double Double.
Automatic Deriving: deriving (Show, Eq, Ord) instructs GHC to generate standard typeclass instances automatically.
Core Rules to Remember
Sum & Product Types: Model domain states with mathematical precision.
deriving (Show, Eq): Automatically generate string representation and equality comparison.
Live Interactive Example
Hit Run Code to see it liveGeometric Shapes ADT
Python 3.12
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Output Console
Click "Run Code" to view the rendered output.
How it works: area uses pattern matching to deconstruct Circle and Rectangle constructors.
Your Turn: Micro Challenge
No pressure! Edit the starter code below and test your solution with instant feedback.
Micro Exercise
Define Direction ADT
- Define `data Direction = North | South | East | West deriving (Show, Eq)`.
- Print `"Direction: "` followed by `show North`.
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Sandbox Output
Click "Run & Check" to test your solution.
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