Advanced Design Patterns in Ruby

Yet another take on design patterns, focusing on the Visitor and Bridge patterns.

Code snippets are here https://github.com/RubyConf-NG/meeetup-snippets/tree/master/ruby-virtual-meetup-2020/advanced-design-patterns-with-ruby

Transcript

1. advanced design patterns implementing with Ruby
2. @igbanam Rubyist — been cheating on Ruby with Java, Crystal, Scala, and Python RubyConf-NG/openemrs 2 poet. person. programmer.
3. contents 3 design patterns Advanced design patterns. Benefits of code structure. Decoupling. the bridge and the visitor The whens and when-nots. The rumours; the pit-falls. Storytelling with design patterns. demo 1 2 3
4. design patterns a glorified copy-and-paste
5. from concept to distribution automation, optimization… brains are naturally lazy why? What are the groupings? What purpose do they serve? categories? Repeatable solutions to recurring problems what? the language has some barriers ruby? code patterns, application, infrastructure, application domains? 5
6. Repeatable solutions to recurring problems • started by architects • adopted into software ◦ “software architects” what are design patterns?
7. categories of design patterns 7 creational The most efficient way to create objects for certain use cases: singleton, factory, abstract factory, prototype, etc structural Ways to layout code for the least pain when maintaining it: composite, adapter, façade, bridge, etc behavioural Organizing dynamic interactions: null object, observer, iterator, command, blackboard, visitor, etc.
8. how does Ruby fare? The good… • flexibility with constructs • robust standard library • no interfaces (fixed in Sorbet) The bad… • no interfaces …currently The ugly… • modules as interfaces 8
9. Application Patterns Event Sourcing, CQRS, Saga, Shared Database/Schema, and so on Architecture Monolith, MVC, HMVC, Microservices, Blackboard, and so on Infrastructure Serverless (lambdas), VMs, CI/CD Patterns, and so on. Communication Service Registry, RPC, and so on 9 patterns could span multiple development domains
10. the visitor a proper way to practise consent
11. concepts behind the visitor pattern • Inheritance ◦ Basic OO • Composition ◦ A Ruby way to feign interfaces • Double Dispatch ◦ Allowing objects define their interaction on other objects at runtime 11
12. Visitor Pattern Source: sourcemaking.com
13. Visitor Demo 13 Say a prayer to the demo gods
14. the bridge a tale of two cities
15. Source: sourcemaking.com Bridge Pattern
16. Bridge Demo 16 Say a prayer to the demo gods
17. Play with it. Learning is a fun process. Design is a Creative Process 17
18. Thank you for your time @yaasky @igbanam 18 Questions?