- Author
- Tuan Anh Bui
- Published
- 13 June 2025
- Kind
- Personal blog post, long guide with code and diagrams
- Original
- bui.app/the-missing-manual-for-signals-state-management-for-python-developers/
- Subject
- Programming languages and types
What it is
Tuan Anh Bui maintains reaktiv, a signals library for Python. The guide opens with a typical Python demo objection. It then sets out a mental model and rules of use.
What it says
- Bui argues signals remove the bug of forgetting to update derived state when data changes.
- Signals invert control: the system tracks dependencies and updates dependents, not the programmer.
- Three primitives are Signal, Computed and Effect, compared to spreadsheet cells and macros.
- Computed values must be pure; side effects belong in Effects.
- Signals update synchronously, so debouncing and throttling should happen before data enters the graph.
- Signals are overkill for simple linear steps, one-shot calculations and request-response code.
What evidence it gives
The guide offers argument, code and many flow diagrams. It contrasts an order service written by hand with a signals version. It describes three scenarios in code. It reports no benchmarks or user results.
Interests and limits
The author maintains the library the guide teaches, so has a stake. The scenario code is illustrative and was not run. The performance claims are stated without measurement. The diagrams are text source.