The document discusses the concept of bounded contexts in relation to legacy code, emphasizing the challenges posed by inherited code that lacks testing and has poor design. It outlines goals for maintaining functional state, adding value, and enabling changeability while addressing resources and approaches, such as using an anticorruption layer for interacting with external systems. The narrative includes examples of user stories and the ongoing efforts to improve the codebase through revisions and proofs.

1. Bounded Contexts
For Legacy Code

2. Bounded Context

3. “a semantic contextual boundary”
— Domain-Driven Design Distilled byVaughnVernon
A meaningful collection of components that meets a
defined, limited, and useful purpose with defined
interfaces and means of interaction with external
actors.

4. Legacy Code

5. “source code inherited from someone
else”
— Legacy Code,Wikipedia
Code that because of its lack of tests, poor design, or
other factors is difficult to work with.

6. Goals
Maintain Functional State
AddValue & Reduce Debt
Permit Changeability

7. Resources

8. Resources

9. The Project

10. The Problems

11. The Approach

12. Account
User
Project
Story

13. Account
User
Project
Story
Account
User
Project
Existing System 3rd Party

14. Account
User
Project
Story
Account
User
Project
Existing System 3rd Party
AntiCorruptionLayer

15. AntiCorruption Layer
Web-hooks
Commands &
Queries

16. Account
User
Project
Story
Account
User
Project
Existing System 3rd Party
AntiCorruptionLayer
Mapping

17. Account
User
Project
Story
Existing System 3rd Party
AntiCorruptionLayer
Mapping
Account
User
Project
Proofs
Revisions
Proofs

18. Account
User
Project
Story
Existing System 3rd Party
AntiCorruptionLayer
Mapping
Account
User
Project
Proofs
Revisions
Proofs
Create Proof
Add Revision
Delete Proof
…

19. Recap

20. Difficulties

21. Achievements

22. Questions

23. James Thompson
Staff Software Engineer @ Nav
@plainprogrammer
theplainprogrammer.com