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Reading Code (Picnic)

Reading Code (Picnic)

As developers, we spend a lot of time learning to write code, while spending little to no time learning to read code. Meanwhile, we often spend more time reading code than actually writing it. Shouldn’t we be spending at least the same amount of time and effort improving this skill? Deliberate practice can help us get better at reading code. Learning how to better read and understand code, can in turn teach us what makes code readable. This might even help us to write code that is easier to read.

In this talk we will discuss the benefits of deliberately practicing reading code in a code reading club or session without an IDE, as well as common strategies to navigate a new codebase and familiarise ourselves with the code using the IDE.

Marit van Dijk

July 09, 2024

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  1. Reading Code We read code when: • adding features •

    fi xing bugs • understanding a new system • doing code reviews • learning new technologies • etc.
  2. Reading Code "developers on average spend as much as 58%

    of their time comprehending existing source code" - Felienne Hermans, The Programmer's Brain
  3. Reading Code • We spend more time reading code than

    writing code • But we don't practice reading code explicitly (much)
  4. Reading Code "How to teach programming (and other things)?" by

    Felienne Hermans https://www.youtube.com/watch?v=g1ib43q3uXQ
  5. Examples of exercises • First glance • Identify components &

    relationships • Most important lines • Identify concepts
  6. Examples of exercises • First glance • Identify components &

    relationships • Most important lines • Identify concepts • Summary
  7. Code Reading Club Learned about ... • reading code •

    other peoples' perspectives • making my own assumptions explicit https://maritvandijk.com/code-reading-club/
  8. Reasons why code is confusing 1. Lack of knowledge 2.

    Lack of information 3. Lack of processing power in the brain
  9. Lack of knowledge • Programming domain • Language / syntax

    • Programming constructs / algorithms • Business domain • Domain concepts • Business logic
  10. Dealing with a lack of knowledge • Create a list

    • Research • Memorise (if relevant)
  11. Lack of information • Unknown details • Unfamiliar names •

    Code connected in unknown ways • Too many things at once
  12. Lack of processing power in the brain • Too many

    processing steps • Too many variables
  13. Dealing with lack of processing power in the brain •

    Memory aids • Dependency graph • State table
  14. State table public class NestedLoop { public static void main(String[]

    args) { for (int i = 0; i < 2; i++) { System.out.println("i is: " + i); for (int j = 0; j < 2; j++) { System.out.println("j is: " + j); } } } }
  15. Understanding a new code base • Joining a new team

    / organisation • Using a new code base
  16. Help in the IDE • Project structure • Build &

    run • README • Dependencies • Diagrams
  17. Find a starting point • Generic • Main method •

    Endpoint • Speci fi c • Error message / Exception • Logic / Functionality
  18. Help in the IDE • Structure • Hints from your

    IDE • Tests • Refactor for understanding • Context
  19. Structured exercises • Code Reading Club: https://codereading.club/ • Code Reading

    Club Resources: https://github.com/CodeReadingClubs/Resources • The Programmer's Brain - Felienne Hermans
  20. Code reading exercise First glance The goal of this exercise

    is to practice getting a fi rst impression of code. (1 min) Independently - Glance at the code Note down the fi rst thing that catches your eye. Then note the second thing that catches your eye. Think about why you noticed those things fi rst.
  21. Code reading exercise Dependency graph The goal of this exercise

    is to get a feel for the structure of the code. (5 min) Independently - Examine structure Variables 1. Go through the code and underline all variables 2. Then draw a link between variables and their uses Function / method calls 3. Go through the code and circle all methods / function calls 4. Then draw a link between methods and their invocations Instantiation 5. Go through the code and draw a box around all instances of classes 6. Then draw a link between classes and their instances
  22. Code reading exercise Most important lines The goal of this

    exercise is to start to think about which lines in the code de fi ne its essence, have the biggest impact or need to be paid close attention to. (5 mins) Independently - Identify most important lines Brie fl y discuss what it means to be important as a group (if you want to). Then, identify the 5 lines you consider most important.
  23. Code reading exercise Concepts (5 min) Individually - Central thematic

    concepts Name the 5 most central concepts of the code. These could be names, themes, classes, or information found in comments.
  24. Code reading exercise Summary The goal of this exercise is

    to think about the core purpose or function of this code. (5 mins) Independently - Summarize Try to write down the essence of the code in a few sentences.