Reading code by Marit van Dijk

Developers spend ~58% of their time reading and comprehending existing code, yet rarely practice reading code explicitly

Code reading becomes challenging due to:

• Lack of knowledge (programming/domain concepts)
• Limited processing power (too many variables/steps)
• Unfamiliar syntax or business logic
• Missing context or documentation

Key strategies for reading code effectively:

• Start with the big picture before diving into details
• Use IDE features (debugging, navigation, type info)
• Read tests to understand intended behavior
• Create diagrams and visualizations
• Break complex code into smaller chunks

Practical approaches to understanding new codebases:

• Verify you can build and run the project
• Review README, dependencies, and project structure
• Identify main entry points (endpoints, main method)
• Trace specific use cases or error scenarios
• Draw dependency graphs and control flows

Code Reading Club methodology:

• Use structured exercises to analyze code samples
• Focus on first impressions and important lines
• Annotate and discuss code collaboratively
• Share different perspectives and insights
• Practice regularly with diverse code samples

Memory aids and tools:

• IDE debugging and navigation features
• Dependency graphs and state tables
• AI assistants for explanations
• Git history for context
• Meaningful variable/method names

Reading code is distinct from writing code:

• Not read top-to-bottom
• Requires different cognitive skills
• Benefits from explanations and context
• Improved through deliberate practice
• Enhanced by collaborative analysis