The document discusses the implementation of the visitor pattern in functional and fluent API design, presented by José Paumard. It highlights the challenges of the visitor pattern and emphasizes a live coding approach to implement it without modifying the visited classes. The document also includes links to additional resources and the author's profiles.

1. #Devoxx
Designing functional and fluent
API: example of the Visitor Pattern
José Paumard
@JosePaumard

2. #Devoxx @JosePaumard
@JosePaumard
https://josepaumard.github.io https://github.com/JosePaumard
https://www.pluralsight.com/authors/jose-paumard
https://www.slideshare.net/jpaumard
https://www.youtube.com/user/JPaumard

3. #Devoxx @JosePaumard
Why the Visitor Pattern?
Because it is tough to implement!
So if you can implement it, then you can implement
anything…

4. #Devoxx @JosePaumard
Live coding!
How to make it functional?
How to implement it without touching the
visited classes?
All with a fluent API

5. #Devoxx
Thank you!
José Paumard
@JosePaumard
https://github.com/JosePaumard/devoxx-belgium-2019-visitor-lambda