Compose Software Like Nature Would

Inspired by biology background I combine some ideas from functional and OO programming into a talk about software design.

Transcript

1. Compose software like nature would @this_ahmed
2. Feature Request
3. Big Ball of Mud
4. software
5. change
6. software as a living organism
7. Earth: 4.5 billion YA
8. Monads: 3.5 billion YA
9. stromatolites
10. The Machinery of Life David S. Goodsell
11. small 1 μm
12. cell membrane boundaries
16. easily replaced
17. messages = colony
18. Bacterial colony
19. –Alan Kay “I thought of objects being like biological cells and/ or individual computers on a network, only able to communicate with messages…”
20. Components: modules, objects, functions, etc. Messages: functions, properties, events, etc. Components with boundaries Compose with messages
21. • easier to reason about (fits in your head) • easier to change (can be re-written) • easier to test (confidence when changing)
23. import myModule from ‘file.js'; // file.js export default function() { return something; } Boundaries
24. Data Fetch Data Filter Line Graph data-fetch.js data-filter.js line-graph.js
25. Data Fetch Data Filter Bar Graph change data-fetch.js data-filter.js bar-graph.js
27. Data Fetch Data Filter Line Graph /project |-- data-fetch.js |-- data-filter.js |-- line-graph.js … 1000 other files What does system do?
28. Multicellular: 1.5 billion YA
29. stove-pipe sponge
30. Mesh Data Fetch Data Filter Line Graph
31. project └── dashboard └── sales-widget ├── data-fetch.js ├── data-filter.js ├── index.js └── line-graph.js
32. sales-widget/index.js // import or inject components // compose our components const sales = dataFetch(“/sales"); const planSales = dataFilter(sales, plan); lineGraph(planSales);
33. side-effects
34. Nervous System: ~600 million YA
35. Nerve Net
36. push side-effects to the edges of our program
37. Data (e.g. fetch api) “Nerve Net” draw (e.g. chart.js)
38. Functional Core
39. pure functions const increment = (n) => { n + 1; };
40. mutable data const array = [3,1,2]; array[0] // 3 array.sort(); // somewhere else array[0] // 1
41. immutable data const array = Object.freeze([3,1,2]); array[0] // 3 array.sort(); // TypeError: Cannot assign to read only property '1' ... array[0] // 3
42. let newArr = [ ...prevArr ]; let newObj = { ...prevObj }; copy data
43. Data Filter Data Shaper Line Graph Options Data (e.g. fetch api) Functional Core “Nerve Net” draw (e.g. chart.js)
44. Data Filter Data Shaper Line Graph Options Data (e.g. fetch api) Functional Core “Nerve Net” draw (e.g. chart.js) Date Filter TrendLine Gary Bernhardt, Boundaries
45. Cambrian Explosion: ~541 million YA
47. Run and Tumble mit.edu
48. Run and Tumble to Better Design small components compose with messages push side-effects to boundaries functional core name things
49. Resources • Gary Bernhardt - Boundaries: https:// www.destroyallsoftware.com/talks/boundaries • Dan North - Software that Fits in Your Head: https:// www.youtube.com/watch?v=4Y0tOi7QWqM • Rich Hickey - Simple Made Easy: https://www.infoq.com/ presentations/Simple-Made-Easy • Jessica Kerr - Functional Principles for OO Development: https://www.youtube.com/watch?v=tq5SQ4W3gRI
50. Compose software like nature would @this_ahmed