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
   

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2. Feature Request
   

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3. Big Ball of Mud
   

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4. software
   

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5. change
   

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6. software as a living organism
   

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7. Earth: 4.5 billion YA
   

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8. Monads: 3.5 billion YA
   

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9. stromatolites
   

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10. The Machinery of Life
    
    David S. Goodsell
    

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11. small
    1 μm
    

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12. cell membrane
    boundaries
    

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16. easily replaced
    

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17. messages = colony
    

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18. Bacterial colony
    

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19. –Alan Kay
    “I thought of objects being like biological cells and/
    or individual computers on a network, only able to
    communicate with messages…”
    

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20. Components: modules,
    objects, functions, etc.
    Messages: functions,
    properties, events, etc.
    Components with boundaries
    Compose with messages
    

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21. • easier to reason about (fits in your head)
    
    • easier to change (can be re-written)
    
    • easier to test (confidence when changing)
    

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23. import myModule from ‘file.js';
    // file.js
    export default function() {
    return something;
    }
    Boundaries
    

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24. Data
    Fetch
    Data
    Filter
    Line
    Graph
    data-fetch.js
    data-filter.js
    line-graph.js
    

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25. Data
    Fetch
    Data
    Filter
    Bar
    Graph
    change
    data-fetch.js
    data-filter.js
    bar-graph.js
    

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27. Data
    Fetch
    Data
    Filter
    Line
    Graph
    /project
    |-- data-fetch.js
    |-- data-filter.js
    |-- line-graph.js
    … 1000 other files
    What does system do?
    

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28. Multicellular: 1.5 billion YA
    

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29. stove-pipe sponge
    

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30. Mesh
    Data
    Fetch
    Data
    Filter
    Line
    Graph
    

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31. project
    └── dashboard
    └── sales-widget
    ├── data-fetch.js
    ├── data-filter.js
    ├── index.js
    └── line-graph.js
    

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32. sales-widget/index.js
    // import or inject components
    // compose our components
    const sales = dataFetch(“/sales");
    const planSales = dataFilter(sales, plan);
    lineGraph(planSales);
    

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33. side-effects
    

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34. Nervous System: ~600
    million YA
    

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35. Nerve Net
    

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36. push side-effects to the edges of our
    program
    

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37. Data
    (e.g. fetch api)
    “Nerve Net”
    draw
    (e.g. chart.js)
    

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38. Functional Core
    

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39. pure functions
    const increment = (n) => { n + 1; };
    

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40. mutable data
    const array = [3,1,2];
    array[0] // 3
    array.sort(); // somewhere else
    array[0] // 1
    

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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
    

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42. let newArr = [ ...prevArr ];
    let newObj = { ...prevObj };
    copy data
    

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43. Data
    Filter
    Data
    Shaper
    Line
    Graph
    Options
    Data
    (e.g. fetch api)
    Functional
    Core
    “Nerve Net”
    draw
    (e.g. chart.js)
    

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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
    

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45. Cambrian Explosion: ~541
    million YA
    

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47. Run and Tumble
    mit.edu
    

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48. Run and Tumble to Better Design
    small
    components
    compose with
    messages
    push side-effects
    to boundaries
    functional core name things
    

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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
    

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50. Compose software
    like nature would
    @this_ahmed
    

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