As part of the course Object Oriented and Functional Programming with Python in university I was instructed to create a simple habit tracking app that can be accessed via a CLI which demonstraing object oriented programming and functional programming concepts.
The project is available on GitHub:
👉 valentinweyer/iu-oop-fp-portfolio
Core Functionality
- Access via command-line interface
- Creating and deleting habits
- Managing active habits
- Analyzing progress and streaks
Tech Stack
To meet the requirements, I built the project with:
- Python 3.12+
- SQLAlchemy – ORM for database management (SQLite backend).
- Click – for building the command-line interface.
- Rich – to improve CLI output readability.
- PyTest – for automated testing.
Design Decisions
To demonstrate OOP, I created:
- A base
Habitclass for shared logic. - Subclasses for daily and weekly habits, showing inheritance and polymorphism.
To incorporate FP, I used:
- Higher-order functions and
map/filterfor certain data processing tasks. - Lambda expressions for short inline operations.
Challenges
- Datetime handling: I initially mixed
dateanddatetimeobjects, which led to subtle bugs until I standardized my approach. - CLI styling: Making the CLI’s help text user-friendly required digging deeper into Click.
- Testing: Setting up proper tests with PyTest was time-consuming but worth it — they caught regressions quickly.
What I’m Proud Of
The extensible habit system is the feature I value most. It allows for:
- Easy addition of new habit types
- Precision in tracking
- A showcase of how thoughtful design principles (OOP + FP) translate into maintainable, adaptable software
Example CLI Usage
Add a habit
Complete a task
Delete a habit
Show all habits
Show all habit instances
Running streak
