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Simple Made Easy

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Key Takeaways

  • We should aim for simplicity because simplicity is a prerequisite for reliability.
  • Simple is often erroneously mistaken for easy. "Easy" means "to be at hand", "to be approachable". "Simple" is the opposite of "complex" which means "being intertwined", "being tied together". Simple != easy.
  • What matters in software is: does the software do what is supposed to do? Is it of high quality? Can we rely on it? Can problems be fixed along the way? Can requirements change over time? The answers to these questions is what matters in writing software not the look and feel of the experience writing the code or the cultural implications of it.
  • The benefits of simplicity are: ease of understanding, ease of change, ease of debugging, flexibility.
  • Complex constructs: State, Object, Methods, Syntax, Inheritance, Switch/matching, Vars, Imperative loops, Actors, ORM, Conditionals.
  • Simple constructs: Values, Functions, Namespaces, Data, Polymorphism, Managed refs, Set functions, Queues, Declarative data manipulation, Rules, Consistency.
  • Build simple systems by: 
    • Abstracting - design by answering questions related to what, who, when, where, why, and how.
    • Choosing constructs that generate simple artifacts.
    • Simplify by encapsulation.

Show notes

Simple vs. easy

  • 1:09 "Simplicity is a prerequisite for reliability". - Edsger W. Dijkstra
  • 1:23 We need to build simple systems if we want to build good systems.
  • 1:27 There is not enough focus on building simple systems.
  • 2:02 The roots of "simple" are "sim" and "plex", and means "one twist". The opposite, which would be complex, is "multiple twists" or "braided together".
  • 2:30 The central point of the talk is seeing software as being folded together or not.
  • 2:37 People usually interchange "simple" with "easy".
  • 2:54 The latin origin of "easy" is the root of "adjacent", which means "to lie near" and "to be nearby".
  • 3:28 Addressing multiple dimensions is important in software design.
  • 3:34 Simple things are those which have one role. They fulfill one task, they have one objective, they cover one concept.
  • 3:56 Simple things may be one dimension of a multi-dimensional problem they attempt to solve.
  • 4:02 Simple things are focused, they do not address multiple issues.
  • 4:12 Simple does not mean one of a kind. An interface does not have to have only one method to be simple. Cardinality does not matter here. What is important is not to have interleaving of issues.
  • 4:49 Simplicity is objective, it can be probed.
  • 5:16 The origin of "easy" implies "nearness". Something that is near can be easily touched or grabbed.

Simplicity vs. easiness in software development

  • 5:58 In software development, easy means being near to our understanding, being in our skillset, being familiar.
  • 6:20 Easy is overrated in the software industry. "Can I get this running in 5 seconds?" It does not matter if the result is a large ball of mud. All it matters is to be done quickly.
  • 7:03 All that is new is somewhat unfamiliar. Do not avoid it even if it is harder to grasp or do at first. 
  • 7:14 People usually feel uncomfortably to say about something that it is beyond their capabilities.
  • 8:17 Easy is a relative term. Something may be easy for someone and difficult for someone else.
  • 8:44 Many times, developers say about some that is simple, but they mean easy, because they mean it is something they are familiar with.
  • 9:05 The distinction between simple and easy is relevant when dealing with software constructs and artifacts.
  • 9:36 The attributes of an artifact are how it runs, what's the performance, how it can be changed over time. These attributes are not the original construct (code).
  • 10:06 People focus too much on the construct, on how easily they can write something or how easily is to replace one developer with another, considering just the familiarity of the tools used, not the simplicity or complexity of the code the new developer needs to deal with.

Why simplicity matters in software development

  • 11:36 We should ask ourselves these questions: does the software do what is supposed to do? Is it of high quality? Can we rely on it? Can problems be fixed along the way? Can requirements change over time? The answers to these questions is what matters in writing software not the look and feel of the experience writing the code or the cultural implications of it.
  • 12:34 "We can only hope to make reliable those things we understand". And there is usually a tradeoff. When evolving a system, making it more extensible and dynamic, it may become harder to understand and decide if it is correct.
  • 13:24 People can juggle only a few things at a time, a small number. The same with the number of things one can think of at one time. That becomes even harder when things are intertwined, because one cannot reason about them in isolation.
  • 13:45 Intertwining raises complexity combinatorially.
  • 14:35 To be able to change existing software one needs to understand it and decide how and where to apply changes. If one cannot reason about a program, he can make those decisions.
  • 15:45 Q: What happened to every bug out there? A: it passed the type checker, and it passed all tests. 
  • 16:08 Having tests should not encourage someone to change code without being careful.
  • 17:35 Only people running very short races can use their maximum speed from the beginning of the race. Some attempt to cheat life by firing the starting gun every 100 yards and call it a new sprint.
  • 18:08 Ignored complexity will slow people down over time. 
  • 18:50 If one chooses easiness, things move fast but accumulated complexity will kill the project over time. If simplicity is chosen, the project starts slower because one has to think things over.
  • 19:35 Easy things can be complex. There can be complex constructs that are succinctly described, familiar, available and easy to use. That is incidental complexity.
  • 21:31 The benefits of simplicity are: ease of understanding, ease of change, ease of debugging, flexibility.
  • 22:35 We can make things easier by bringing them at hand, by becoming familiar through learning.
  • 23:19 We can’t suddenly change our brain to grasp something complex. We need to simplify complexity so we can handle it.
  • 24:24 Because we are limited in how many balls we can juggle in the same time, we need to decide how much incidental complexity vs. problem complexity we want.
  • 27:35 "LISP programmers know the value of everything and the cost of nothing."
  • 28:08 Programmers like to emphasize only the benefits of a new new tool or method, but they rarely mention the downsides or the tradeoffs.
  • 28:50 Complex: state, objects, methods, vars, inheritance, switch, matching, syntax, imperative loops, actors, ORM, conditionals, inconsistency. Simpler: values, functions, namespaces, managed refs, polymorphism, data, set functions, queues, declarative data manipulation, rules, consistency.
  • 31:36 "Complect" means to interleave, to entwine, to braid. Complect results in bad software.
  • 33:08 Complect means to braid together. Compose means to place together. Composing modular components is not simple if the modules are highly interconnected.
  • 34:30 Simplicity enables partitioning (horizontal separation between components) and stratification (vertical separation). 
  • 35:40 State is easy but introduces complexity because it intertwines value and time. State intertwines everything it touches directly or indirectly, and it is not mitigated by modules and encapsulation.
  • 38:00 vars or refs do not make state simpler.

Constructs that generate complex artifacts

  • 39:27 The following constructs are complex because they intertwine ...:
    • State - everything it touches
    • Object - state, identity, value
    • Methods - function and state, namespaces
    • Syntax - meaning, order
    • Inheritance - types
    • Switch/matching - multiple who/what pairs
    • Vars - value, time
    • Imperative loops - what/who
    • Actors - what/who
    • ORM - OMG

Conditionals - the rest of the program

  • 42:58 One can better write sophisticated systems with simpler tools that let one focus on the system rather the constructs of the language or tool.

Constructs that generate simpler artifacts

  • 43:50 The following constructs are simpler:
    • Values - use final, persistent collections
    • Functions - use stateless methods
    • Namespaces - use a language with good support for namespaces
    • Data - use maps, arrays, sets, XML, JSON, etc.
    • Polymorphism - through protocols, type classes
    • Managed refs - Clojure, Haskell
    • Set functions - via libraries
    • Queues - via libraries
    • Declarative data manipulation - via SQL, LINQ, Datalog
    • Rules - via libraries or natively in Prolog

Consistency - through transactions or values

  • 47:22 One needs to learn to live with environmental complexity: CPU, memory, inherent complexity related to implementation (GC, for example), etc.
  • 49:05 Programming is not about typing on a computer keyboard, it is about thinking.

How to build simple systems

  • 49:17 Build simple systems by: 
    • Choosing constructs that generate simple artifacts
    • Abstracting - design by answering questions related to what, who, when, where, why, and how
    • "I don't know; I don't want to know." - simplify by encapsulation.
  • 50:38 Answering What 
    • What do we want to accomplish? 
    • Use the constructs available - interfaces, protocols, type classes - to create sets of functions, and make them abstractions. 
    • Give them names. 
    • They are specifications, not implementations. 
    • Make them small. 
    • Use polymorphism to keep them small. 
    • Create interfaces at this point not implementations, to avoid introducing complexity.
    • Let how is to be done to be solved later by yourself or someone else.
  • 52:40 Answering Who 
    • Define the data or entities your abstractions are going to use.
    • When building larger components, pass the subcomponents as arguments. Do not hardwire them into their parents.
    • Build with more components rather than fewer.
    • Do not complicate a component by getting into the details of a subcomponent.
    • Do not complicate an entity with the details of another entity.
  • 53:46 Answering How
    • This is where implementation details are fleshed out.
    • Use the polymorphism defined earlier as much as possible.
    • Isolate an implementation as much as possible to avoid tying it up with others.
  • 54:40 Answering When, Where
    • Avoid introducing complexity by tying things together.
    • Avoid connecting objects directly by using queues.
  • 55:32 Answering Why
    • Avoid introducing complexity when implementing policies and rules.
    • Rules tend to increase complexity through constructs such as conditionals, flow control, etc.
    • Try using a declarative or a rule system to keep things simple.
  • 56:06 Information is simple. Keep it simple. Don’t use an object to handle information. That’s not what objects were meant for. We need to create generic constructs that manipulate information. You build them once and reuse them. Objects raise complexity in that area.
  • 57:00 If you have a map, use a map construct. Don’t create an object for it. Leave data as data. Do not tie data logic to its representation. Avoid ORM.
  • 57:20 Choose simple tools. Write simple stuff. Simplify other people’s work by disentangle it.
  • 58:10 Simplicity is a choice. We have a culture of complexity. Avoid tools (languages, constructs, etc.) that generate complex outputs. Simple != easy. Look for complexity and avoid it. Reliability tools - testing, refactoring, type systems - are good but secondary. They do not enforce simplicity. They are just a safety net.
  • 59:53 Make simplicity easy by:
    • Using constructs that generate simple artifacts.
    • What matters are the artifacts not the authoring tools.
    • Simplify the problem space before starting.
    • Use abstractions aiming to simplification. Design a bit upfront.
  • 1:01:15 "Simplicity is the ultimate sophistication." - Leonardo da Vinci.

Languages, tools and projects mentioned

People mentioned

See more presentations with show notes

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Category Theory for the Working Hacker

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Rust: Systems Programming for Everyone

Recorded at:

Oct 20, 2011

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Community comments

  • Video release schedule

    by Alex Miller /

    Your message is awaiting moderation. Thank you for participating in the discussion.

    If you're interested in other upcoming videos from Strange Loop, the full release schedule is here. If you want to be notified for Strange Loop in the future, sign up for the mailing list.

    BTW, the category theory and monad references in the talk were in relation to Erik Meijer's talk earlier in the conference which unfortunately was not approved for release.

  • Download Slides

    by Amit Shah /

    Your message is awaiting moderation. Thank you for participating in the discussion.

    Where can I find a link to download the slides of this presentation?

  • Re: Download Slides

    by mikhail franco /

    Your message is awaiting moderation. Thank you for participating in the discussion.

    I guess they will be here on github when ready:

    github.com/strangeloop/2011-slides/blob/master/...

    Mik

  • Re: Download Slides

    by Alex Miller /

    Your message is awaiting moderation. Thank you for participating in the discussion.

    Rich asked for his slides not to be made available separately as he prefers them to be considered in the context of the talk.

  • Re: Download Slides

    by Oli Fante /

    Your message is awaiting moderation. Thank you for participating in the discussion.

    Mediafire to the rescue: www.mediafire.com/?ar3gv7ql7zcuqx3

  • complects

    by Vic Ripa /

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    There is an interesting overlap between the notion of "complect" as interleaving of concepts and the notion of entanglement in software, as discussed in an ongoing series on the "physics of software" by Carlo Pescio. Here are two relevant links:

    www.carlopescio.com/2010/11/notes-on-software-d...

    www.carlopescio.com/2011/01/notes-on-software-d...

    they can be easy followed even without reading the previous chapters :-)

  • Simple version of "Word Origins"

    by manuel gonzalez /

    Your message is awaiting moderation. Thank you for participating in the discussion.

    Etymology

  • Re: Download Slides

    by Amit Shah /

    Your message is awaiting moderation. Thank you for participating in the discussion.

    Mediafire to the rescue: www.mediafire.com/?ar3gv7ql7zcuqx3


    Thank you !

  • Re: Download Slides

    by Andrew Gwozdziewycz /

    Your message is awaiting moderation. Thank you for participating in the discussion.

    The slides are helpful for people who can't watch the video, say because they're using Gnash or something, and need to download the MP3 to follow along.

  • Nice, funny but without examples - useless

    by Sławomir Sobótka /

    Your message is awaiting moderation. Thank you for participating in the discussion.

    Comparing Easy and Simple in this form is brilliant. But in this form they are also just Your personal opinions. Projection of Your "inner mental model" of programming, modeling etc.
    What is missing, are facts. Maybe examples of non-trivial and non-hello-world problems and code/diagrams with some sort of measurement of complexity.
    Personal opinions can be considered but only in the context of some kind of psychological personality types that determines "feeling" of complexity.
    That could also help preaching Clojure:)

  • Re: Nice, funny but without examples - useless

    by Rafal Babinicz /

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    Sławek, you sound like you didn't USE any functional language at all? And you totally dismiss fact which says "Rich Hickey, the author of Clojure, [...] with over 20 years of experience"
    If you want more then his words, you can SIMPLY study some real word examples here: github.com/search?langOverride=&language=Cl... and watch maybe: blip.tv/clojure/clojure-for-java-programmers-1-....

  • Re: Download Slides

    by Peter Damoc /

    Your message is awaiting moderation. Thank you for participating in the discussion.

    a smaller and nicer version:

    www.mediafire.com/?anvd1bb5218ja2r

  • Rich Hickey keynote at Clojure/West

    by Alex Miller /

    Your message is awaiting moderation. Thank you for participating in the discussion.

    If you liked this talk, you might be interested in attending the new Clojure/West conference in San Jose, CA, March 16-17th. Rich Hickey will be doing a keynote at Clojure/West, along with Stuart Halloway, Bradford Cross, and Richard Gabriel.

  • Your message is awaiting moderation. Thank you for participating in the discussion.

    Thanks for this excellent talk, it actually aplies to more than just software. If you stretch this simplicity all the way to the customer's needs, I'm sure the value of our work will be better for it.

    When trying to split things up, some developers are actually uncomfortable of having many components because that feels like it will be hard to find out what is happening where. When working with queues, it's are harder to debug a program.

  • Jugler

    by Erik van Oosten /

    Your message is awaiting moderation. Thank you for participating in the discussion.

    The most amazing jugler I ever saw was in Cirque Soleil could handle 21 balls. Yes, 21!

  • Your message is awaiting moderation. Thank you for participating in the discussion.

    Thanks, this is a very nice video!
    Also, I'm a fan of Clojure and other multi-paradigm languages (like F# where "active patterns" is kind of "multi-methods").

    Some comments:

    1)
    "Clojure and Haskell refs compose value and time"... So is this like reactive programming?
    Like programming set-operations against a set of events (event storage/event loop/audit trail/transaction log/history/whatever you call it)?

    2)
    Pattern matching is very close to multi-methods ("polyphormism ala carte").
    Multi-methods can be used to separate the reasoning from the method. So, yes, you can think it makes this one method simpler. But there is still this reasoning somewhere.
    "Polyphormism ala carte" has its places, but replacing matching everywhere as best practice would just hide information (a bit like IoC).

  • Great, but ...

    by Chris Partridge /

    Your message is awaiting moderation. Thank you for participating in the discussion.

    Great talk. Neat idea to contrast the tension between easy and complex. Liked the examples.
    However, there is one aspect of complexity that I felt was not really explicitly addressed. This is that a braid like structure is the hallmark of high levels of functionality in nature (see e.g. Figure 9.1 in Reengineering Philosophy, which compares the decomposition of a lump of granite and a fruit fly, illustrating what the book calls descriptive simplicity and complexity). If we want to build highly functional systems, then the challenge is to find some way of capturing descriptive complexity with lego-like components (sometimes called deep simplicity).

    Chris

  • notes from this talk

    by Suraj Gupta /

    Your message is awaiting moderation. Thank you for participating in the discussion.

    I posted notes from this talk (with bits from the 2012 RailsConf talk):
    obeautifulcode.com/Craftsmanship/Simple-Softwar...

  • Citations

    by keynan pratt /

    Your message is awaiting moderation. Thank you for participating in the discussion.

    At about 17 min you show a graph which you say is made-up.

    Is there any scientific basis for this inference? Can you point me to the literature?

    Thanks

  • How to watch this?

    by Owls Rutherford /

    Your message is awaiting moderation. Thank you for participating in the discussion.

    Is this a playable video? All I see is the mp3 link... infoq fail.

  • Your message is awaiting moderation. Thank you for participating in the discussion.

    x

  • Pseudointellectualism

    by It's Me Yo /

    Your message is awaiting moderation. Thank you for participating in the discussion.

    Yet again, another talk that takes a personal, negative experience and paints it as gospel.

    That crap about the starting pistol, about rebuilding stuff that has been done already may well be applicable to the author's projects, to the author's experiences. But I would posit this: how about you've just been working in bad company, and in a bad company. Because I do t experience the same stuff you do. The key difference is that just because I have experienced it one way, it doesbt mean I am going to pretend that my personal experience is the norm, or should be a basis for a new religion. I can look at it objectively and think to myself: well it looks like this stuff works and this stuff probably doesn't work... in this particular situation.

    The thing that irks me with a lot of Medium posts and talks like this is that it's usually a relatively young protagonist who has a limited amount of experience to draw on but insists (not thinks, not hypothesises) but insists they have the answers. These kind of arrogant statements produce a revolution one in every hundred. That's not to say discussion isn't valuable, but of there were less arrogance and more objectivity we would spend less time chasing false idols and more time making progress.

  • Re: Pseudointellectualism

    by Shalok Shalom /

    Your message is awaiting moderation. Thank you for participating in the discussion.

    This sounds a lot like pseudointellectualism to me.

    How is Rich Hickey, one of the most respected and quoted programmers on earth, a relatively young protagonist who has a limited amount of experience to draw on?

    And how is this based on his bad experience without any evidence?

    Did you even watched the whole video?

  • Transcript of this talk is available

    by Andy Fingerhut /

    Your message is awaiting moderation. Thank you for participating in the discussion.

    A transcript of this talk is available here: github.com/matthiasn/talk-transcripts/blob/mast...

  • Re: Pseudointellectualism

    by Vinay B. N. /

    Your message is awaiting moderation. Thank you for participating in the discussion.

    Good troll.

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